When you have an older home with everything needing to be replaced, how do you prioritize and find a stopping point?

I have a home possibly built in 1900s. It’s 1000 sq ft 3 bed/1 bath family home that needs a lot of work. My brother lives there only so I agreed to help him fix the place up while he lives there. So I’ve been talking with contractors and they say the house needs a new roof. I am going to do a new roof but the guy is talking about insulation because the house doesn’t have any, siding replacement, window replacement, replacing the porch. I am incredibly overwhelmed and I don’t have much money to do the rest. This year so far, I’ve done 7k in foundation repair and I did kitchen, bathroom, and bedroom work for $35k. How would you tackle this situation?