Inherited house - two siblings looking to buy out one other

The fact that your partner is does not want "in" is an alarm bell. I understand you want to care for your brother but there are other ways to provide for housing him that don't impact your own financial future and that of your family.
 
I agree with those suggesting to sell now. There are too many scenarios where this arrangement could go wrong. If your brother were to meet someone and move them in, they might not want you coming to stay, despite you owning half. You are adding debt to your own family and for what gain- to have a bed whenever you wish to visit 'home'? I wouldn't support my partner in such an arrangement unless there was a regular income, either from renting rooms or your brother paying you rent for the long term use of your share. You do need to separate heart from head. Once the parents are gone it really isn't 'home' anymore, as we soon realised. Sell up, each take your share and your brother can surely find a suitable place with his share plus a small mortgage.