I come here having two difficult days in a row that have culminated in tears and I am reminded by your post that life is about the here and now. We can only do our best and let God handle the rest.
I hope your husband's family is only showing signs of their grief with their behavior. Maybe their hurt has caused them to want to detach now and think of him more as someone else's husband who died in prison rather than their own son. Maybe seeing it come from a place of pain will help you to cope with it as well.
There have been some heartfelt suggestions here and I know you will find a thoughtful way to honor his passing for you and your children.
Please keep posting. We care and want to hear from you and know that you are working through this.
Much love,
Alice