@jensen995,
And this is why most remarriages end in divorce....
All around, it seems no one is happy. But here's some truth:
As you know, a will is the ultimate way to disperse your worldly goods after you die. It sets proportion to the remaining assets AND debts that someone leaves behind. However in some cases, a will can be disputed under certain circumstances.
This might be one of them. A remarried spouse IS entitled to the first $20,000 of the estate PLUS a 1/3 share of the balance. So, yes, he does have a legal leg to stand on, but that means proving in Probate Court why his wife's wishes can not followed due to incapacitation. It also matters if his name is on the deed to the property, because regardless of a will, you wouldn't be entitled to his share, only hers. He may also get EVERYTHING, house, cars, bank accounts, personal property.
There's a ton of ways the estate can be divided. You can designate a life estate, where he has control of the house until he passes, then it reverts to you and your brother.
Or, you can try to kick him out, sell it and go from there. (Not advisable).
What IS advisable is to stay out of it. It's their marriage and their house. Let them figure it out.