I don't know what the law is like where you are, OP, but you may be able to contest that. That is a cruel and disgusting dick move on the part of your grandfather, and I think the courts would agree. Good luck!

I have considered giving my brother a similar kind of offer and I am not even dead yet.

Could always maje a deposit at a sperm bank (and of course get paid for that) and then get the vasectomy, gaining $3,500, minus the cost of the vasectomy.

I'd go for it. Save some baby batter in a bank and then get the vasectomy. $3500 I didn't have is now in my pocket and bills or other expenses can get paid.

do it, get the money, get it reversed

Yes because you can control if you are born to married parents or not.

$3500? Not worth it. If you want to throw away money so badly, at least put it towards something useful like a charity.

I hate family like that. You didn't ask to be born out of wedlock, therefore, they shouldn't be treating you like garbage. They're the ones who need to be looked down upon. Why should it matter anyway? Marriage only provides financial benefits, in most cases, to the beneficiaries. It shouldn't determine whether or not your family loves you. You're still their family by blood. If they can't appreciate you over something out of your control, then good riddance on them!

You could've gone to the sperm bank and left as much as you could.