What is going on here?

I want to give some background information on a death and then ask some questions for you to ponder and maybe even respond to.
I know a man who’s mother died nearly sixteen years ago.  She had cancer for several years prior to dying.  When she died, she had been living several states away.  She had however been living in the same town as her son, in a home he had bought for her to live in.  The man’s sister came into town to be with their mother while she was sick.  The sister and brother did not have a good relationship with each other prior their mother being sick.
The sister believed that her brother had been taking advantage of their mother, by requiring her to pay rent and utilities on the house.  She also felt that the grand kids had taken advantage of her as well by having her babysit her great grandchildren.
The brother believed that charging the same rent for ten years at the price of what was paid for a two bedroom apartment ten years prior, was fair and that his mother wanted to pay something for the house.  The brother also has from his perspective tried to help out his sister with giving her a car when she needed one and even some money from time to time.
Some of the descriptions given are not related but then again they are.  It provides some perspective of what each may be feeling about each other in addition to the previous estranged relationship they had over the years.
The next details I can only give from the perspective of the brother.  The previous details were gathered from information from both of them.  One day while the sister was visiting, she took her mother to the bank and paper work was signed to make the sister power of attorney over her mother’s affairs.  The brother believes that his mother was on such strong pain relievers that his mother was not able to comprehend what was being done.  Then later in the evening, the sister and mother left in the mother’s car and drove to the sister’s home several states away.
From the sisters perspective she may have believed since the mother had lived in the same town as her brother for so many years, that she wanted her mother to be with her for a little while before she passed away.  In order to do this, some of the funds in the bank were needed to cover moving and living expenses.
After their mother passed away, she was transported back to where her son lived and was buried with her husband who had passed thirty plus years earlier.  All the time of the wake and funeral, there was little to no conversation, between the brother and sister that took place, aside from what was needed to make the arrangements for the wake and burial.
Upon the sale of the house, it was found that many very personal items had been removed from the house that his mother lived in.  Items of a personal nature for his mother and for others as well that she had always held on to.  The remaining items were packed up and brought back to his house.  Some of the larger items were given to relatives and to be honest I am not sure what happened to the majority of the belongings.
For several years most of the belongings remained in a boxes in the brothers house.  Eventually the items were gone through and laid out on his pool table.  Each time family members came over and were in the basement, he would ask if they wanted anything of his mom’s.  Numerous of the items were not even family related but items that would have had meaning only to her because of some baby sitting she had done or other people she had meet.  The best I can recall, those items have been on the pool table for nearly six years now and are still today.  So if we look at the number of years ago she passed until when they boxes were went through was about ten years.
To this day the brother and sister do not speak, unless absolutely needed.  I am not aware however of any contact in the last several years.
Are there still unresolved issues?
Has the brother grieved yet?
Is the brother still grieving?
Has the brother come to terms with the loss of his mother?
Has the brother reconnected his loss in a different way?
There are so many more questions as well that could be asked.
Maybe you have some questions to ask, maybe you have some to ask and answer for this post.