I am literally reeling from a year in which my oldest brother died, and 7 months later one of our closest family friends died. He was also my husband's best friend.  Both of these men and their wives made up a major part of our social circle.  
Just prior to these deaths, my husband and I very nearly got divorced after 30 years, and we barely pulled it back together a month before my brother's death.  
I think the most difficult question I have is, why is my sister in law so withdrawn from me and my husband?  
By all accounts, she and my brother were frequently or almost always at our home when we had guests; we considered them friends.  I took her out once for dinner with another friend, dropped by several times, and thought everything was fine shortly after the death. 
My husband helped her from the first, loaned her money, and did whatever she asked.   He was the first person she called when she found my brother dead on the floor. I did as she asked:  calling all my relatives and inviting them to stay over at my house the entire week to keep them out of her house.  I never received a thank you for this even though it was a considerable effort and, I thought, of great value to her.
She had to close out my brother's business and called back an ex-employee (who lied to me, insulted my brother to my face, and took credit for all the good of my brother's business in the course of two conversations).   He took full credit for the success of my brother's business in the same conversation.  He told me point blank, twice, he did not intend to continue in the same line of work as my brother.  I knew he and my brother had had a disagreeement about the direction of the business as my brother confided this in me, so I doubted the employee's assertion.
When I mildly expressed concern that this ex-employee maybe had a conflict of interest, she defended him.  
I told him I wanted to purchase, in accordance with my sister in law's wishes, several pieces of equipment off my brothers' floor inventory, the week I met with him, then I asked for two more weeks after a week had passed.    My sister in law said she had as much as a month or more  in the future to finalize the sales so the time was not an issue for her.
When I asked for more time to purchase three expensive items off his floor inventory (due to my marital issues pending), the employee freaked out and revoked his offer to me, by email.  In response, I sent him an email telling him he had the emotional intelligence of a gnat, which he did, in criticizing my brother's sales ability to my face at the same time trying to sell me my brother's inventory, and in trying to high pressure me into paying for inventory for which he'd never even sent me an invoice. there was never any question that I was good for the money, by the way.
His response, not to me, was to tell her she should sell everything that week at an inventory sale.  I found out about the saturday sale of the pieces I'd asked for when I came home from a business trip on Friday night, the sale was Saturday. 
The morning they were holding a sale of his inventory I showed up early to discuss the business of the equipment with her, but my remaining two brothers were already there helping out.  When she saw me she immediately started screaming at me in front of them, criticizing me for things I did (but that I asked her permission for in advance and that she had given me permission to do).   I was so schocked and upset at her patently unfair accusations, I did not respond except to say I was sorry I upset her, and I left.  I was too upset to stay.   They sold the inventory I had requested that morning after I was screamed out of her house.  I wrote her a note the next week saying I did not understand her behavior or anger toward me, that my husband and I had been gracious and accommodating and that I had not done anything without her getting a chance to object.  She replied by returning the money that my husband had given her for funeral expenses--that offended him. 
She continues to have business dealing with her employee, the business got closed out but as I predicted he has opened a competitive business in the same line of work as my brother's.   
I saw him at a trade show recently and spoke to him; he seemed surprised that I was friendly.  There was a memorial service to my brother at the industry show and neither myself nor my husband was invited; I do not know who else was.   I had asked about her plans there, but never got a response; I have not gotten a response about several minor things I have emailed her about. One example:  I offered to return a sewing maching which she gave me to store when they did not have enough room at the house.  Now she has room.  No answer at all. 
My other siblings were allowed to buy things at the sale and were given things from my brother's estate, my husband was also given things.  She offered me one of his books but never has arranged a time when I could come over, she's always been too busy.  
In the last 7 months, she had us over once with our grown kids and has declined all of our other invitations over 7 months.  Last week we invited her to watch football with us, she said how about next sunday, we said yes.  On tues she showed up for my brother's birthday at a restaurant and my husband confirmed the date for today.  Today she never showed, when he called her, she had no excuse, saying since she did not hear from us (a third time) that she went hiking with a friend.  She only called us at 5 when she saw my note from a two oclock game.   She went out with a friend and my husabnd's assessment was that she had but a lame excuse.  My husband and I were both upset and perplexed, my daugher was upset, but what are we to do?   
I think we both made some errors in the short term about the business communications but I hold no grudge against her, I do think her employee was a jerk and I know my brother shared that opinion.  I don't understand why she would feel more loyalty or friendship with him than with us, that she would even feel she had to make a choice.  Especially if the business invetory has now been closed.  Those communicatons lasted about two weeks and that was over 4 months ago or more.
Why is this so screwed up?  She speaks with and sees my other brothers, my sister, my neices and nephews.  Is there anyway for me to bring this to closure?  
She lost her mother as a teenager after a long bout with cancer, her father also died a while ago and she has two older sisters who came out to help pack up my brother's belongings the first week.  
I remember at one point she got mad becuse I said that loosing my oldest brother was as bad as loosing a husband--of course my husband and I were not getting along then and my brother was closer to me in life than anyone including my parents, neither of whom I had a nurturing relationship with after childhood, but my dad was good to us the last few years of his life.  
I can't help but think her process over her mom has caused some deep seateed repressson or denial about some issues that have led her to these behaviors.  She also has no brothers and has a parent/child relationship with her older sisters I suspect.   Any help is appreciated.