My son's girlfriend is divorced and the ex was ordered to pay child support. He lives in IL and she in MO. He has NOT paid support and because he has warrants outstanding against him for his arrest. He is re-married and has a child again. He now approached his ex (my son's girlfriend) saying he would like to sign over his parental rights to avoid going to jail, and not having to pay any child support in the future. First of all I feel he should pay for all the legal fees, if he wants this and not her paying the attorney.

She wants to go for this and has an attorney, who does not seem to advise her correctly (or she is not telling all) in this case.
So far she gets MC-plus from the state (MO) to cover Health insurance for her little 5 year old girl. Would she not loose this coverage, if she let's the father of the hook?

I read and heard from people that it is not easy to give up parental rights, unless there is sombody is WILLING TO ADOPT THE CHILD, or abusive circumstances. It would also not prevent the ex- from going to jail from the past issued warrants. Why is her attorney not advising her about this, instead he wants a $2,000 payment already.

Could it be that my son's girlfriend is not telling him the truth and told her attorney that he will adopt the child?

Their releationsship is not solid anymore, the reason he is still staying on longer is because of the child. He has paid a lot of money for her over the last few years, but he made it very clear to her that he will NOT marry her or adopt the child, nor does he want any children of his own.
She has manipulated things before, and I am afraid she is doing it again, with the hope to change my son's mind or trap him otherwise.
Personally I think nobody should stay together if things are not working out, it stresses children out if they have verbal disagreements and pretty soon the child will play them out against each other, that is normal. Please if you could answer the legal questions that would be a big help.

I also feel she could agree that he would not have to pay child support if that is what she wants, but not let the ex-husband totally of the hook for the child's sake. She dicorced him when the girl was 9 months old and found my son while she still was processing the divorce, looking for fast support I guess. I know I sound bitter, and I am a little, feel like she is using right now.

He now approached his ex (my son's girlfriend) saying he would like to sign over his parental rights to avoid going to jail, and not having to pay any child support in the future. First of all I feel he should pay for all the legal fees, if he wants this and not her paying the attorney.
Rights and obligations are two different things.
There are many voluntary/involuntary terminations of rights cases where the child support remains.
Who and how many has to pay is a judge decision.

Legally your son has child support obligation until the child is removed from his home.
You can see the grounds for TPR in Illinois here:
Grounds for Termination of Parental Rights Illinois - (http://library.adoption.com/articles/grounds-for-termination-of-parental-rights-illinois.html)

The ex is to pay support, and I don't believe Ill will allow an adoption unless they are married, ( and I think 6 months to a year)

And all past support is still due so that would not stop ex from going to jail for non payment.

And the attorney will attempt to send in the paper work ( it can be sent to the court) and my guess that there is a 5 or 10 percent chance it may be accepted, but even if he gives up his rights, normally the court will not stop child support anyway.

So my opinion, the attorney will do it , and file it and try for 2000 dollars plus more when he has to appear in court ( my guess) That is their job to try and win, even when they know it is doubtful, if you hire them to try.

So she should tell him to start paying or go to jail, why should she care