Sperm donor

This is a bit complicated so I have a man J we don't have a title to our relationship but we are monogamous and have been for almost 9yrs we don't want to get married or live together but I do want kids J doesn't want to father children he has some very serious genetic health related issues he doesn't want to pass on J has an older brother T who already has a kid 11yrs old T recently mentioned that he would like to have another child but he is single and isn't really dating he doesn't want to be 40 when he has another baby T is 33 when T brought this up J said he should find a surrogate if he was serious the conversation dropped off shortly after and we went back to our game me and J and T spend a lot of time together anyway after that I kept thinking about it and when we came home from our visit with T I asked J if he thought it would be weird or uncomfortable if I asked his brother to be my sperm donor/baby daddy ...... He actually said he thought about it too since he knows how much I want kids but thought it would be weird and upset me if he just threw it out there without talking to me first so we talked a little more and decided to talk to T and see if he is up for it ... I know most donors don't have rights to the child but since J doesn't really want to be a dad in general I would be fine if T was involved as the father not just being a donor unless that's what he wants we will be doing it at home if I says yes does anyone have any advice or been through anything remotely similar?