How do I go about helping my kids father gives up his rights forever for our two boys and unborn child what should I do?

It's a very difficult process. The court will usually not take away/let a parent give up their rights unless they pose a threat to the child(ren).

If I can ask, why does he want to reliquish his rights?

Because he stupid and he's with this lady whose have two kids and separate from her husband,and when I ask him to do for his kids and my unborn child he threating me with am give up my rights if ai keep bother him

Then divorce him and ask for the maximum allowed for child support. He can't just give up his rights like they're a pair of socks.

He can not just "give up his rights" well he can never go see them, never visit and have anything to do. But you go to court and file for child support, he sends you the monthly check and you don't worry about him,

If he says, I will give up my rights, just laugh at him.

He's on child support that's why he keeping saying he's want to give up his rigths with our two boys and unborn baby,can he do that

Never if you don't want him to, and very seldom if you agree unless you have a new husband who wants to adopt.

As said he can't just give up his rights. So, don't worry about those threats.