Property Advise o?

Your best option would be to see a lawyer to make sure things can get setup the way you want for your son and brother.   Your bother would likely expect a certain % of the house that may even exceed $100k which would only be fair, but you just need to make sure it gets legally documented and you and him are in agreement.  Otherwise it depends on what your options are for downsizing and if your current home is a realistic option to retire in the long run.  Houses with a lot of stairs or that require a lot of maintenance you can't afford to hire out for will be very problematic as you get older, so it can be better to move now when you are healthier.   You do lose a lot of money in the selling process in fees so if you can stay you save all that.

Rather the place him on the title, give him a purchase money first mortgage for $100,000.  You could even structure it so that there are no payments until date certain.  When your son inherits the home he would then have to get a mortgage to pay off your brother.

Just because your brother is on the deed does not mean that your son won't receive the inheritance.  Deeds are written to apportion share.  Consult a lawyer.  Your son will inherit his share of the house, if you leave it to him.

Before you do anything, talk to a financial advisor about your situation if you need money.

Finding a cheaper house is certainly a better option than getting your brother involved.