How can I encourage my Father-In-Law to set up Durable Power of Attorney and Estate Planning?

Geez, sounds really bad. How would your husband be responsible for his adult sisters? Is this a situation where he will only inherit the house "if" the sister can stay?

I feel your pain about the POA, etc. Was like pulling teeth to get Mom to do this. Then she leaves me off of everything. I have voiced my opinion about this and told her I will not seek guardianship of her if my brother should die. I mean it. (Guardianship is what you have to do if there is no POA in place and the parent is incompetent) I have a son in law who practices family law and he advised me to make a good faith effort to help, then walk away. Seeking guardianship is very expensive and time consuming. So I warned her up front and she is competent, so she should understand the situation. Tell your FIL if one of the daughters seeks guardianship of him and they are granted the guardianship, he loses all his rights and the guardian takes complete control. Of course a judge probably wouldn't grant either sister guardianship, but FIL doesn't have to know that. Maybe that will work.

Thank you for your response. The situation here is different. One of his daughters was verbally and emotionally abusive to him. We had to have her legally evicted from the house. She also has stolen most of his tools to sell for drugs and has threatened him.
The other daughter is not as bad and I do not really have a problem with her. She lives in the home.and collects disability for some type of mental problem.
My husband just does not want to be financially responsible for any of his sisters and we believe the father may have some type of stipulation in his will.

Many problems here as far as who gets the house. If husband wants the house then he needs to ask his father if he is leaving the house just to him. If not, then you have to understand there will be a division of assets upon his death. That said, I have mixed feelings about people who give the "deserving child" everything and leave the others out. It makes for long lasting resentments. However, i do understand when one child takes care of everything and the others do nothing, the siblings deserve nothing. But, in the end, it is up to FIL to do what he wishes and he may be mum on the subject due to not wanting to make your husband angry, and leave out the other children. As a parent, I would hate to have to make such a judgement. But I do understand where you stand. If your FIL gives or leaves the house to your husband, then be prepared for some complaints from the others. There are many who post on this site who believe everything goes to the child who helps. For me, I have tried my best to be part of my Mother's care but have been written off because I moved out of state. So make sure the other's don't really want to help and are not being pushed away. I am sorry if this sounds like I am judging you, I am not, I just happen to be in the position of the "not helping" child because I have not been allowed to. God bless.