These family situations are always very difficult. Everyone has different expectations and needs, and these can get confused with sibling rivalries or resentments that date back to childhood. The best thing to do, if possible, is to have a full discussion of all of the issues around your mother's care and expenses, starting with each of your hopes and expectations. Ultimately, any agreement should be put in writing, not because you would sue one another if the agreement were breached, but because it's a way of making sure you're both on the same page. This kind of discussion often needs to be facilitated by a mediator or attorney to make sure it doesn't break down in bickering. You may need more than one meeting. And, since you live in different states, some or all of the conversations may have to take place by telephone.