Giving up rights

I've been in the process of a very very long divorce with my husband even though he was the one who walked out initially. The whole process was stretched out because he was scared he'd have to pay child support and he was abusive so I was terrified to push things in the beginning. It took me eventually dating someone to give me to courage to start making things happen faster. For awhile we were floating around in the system because I didn't know where he lived or anything. He recently got the papers served by a Sherriff at his work finally! Yay! And he called me and finally said he just couldn't pay child support and wanted to sign his parental rights away. In our state, you can not usually willingly terminate rights unless a step parent wants to adopt. My boyfriend and I have a child together a plan on getting married as soon as my divorce goes through. He is the one who raises and provides for both of my children. He considers my first child his son and wants to adopt him. When my husband agreed to this, I was honestly happy. I feel it is one of the few things right he has done for my son. My husband is a recovering addict and I know if a child support order is put on him he will just go to jail and it is the state that is pushing for child support not me. My family was happy my boyfriend wants to adopt my son when we get married but they wanted to trash and bad mouth my husband for signing his rights away and not taking care of his son. I'm not saying he's a great dad for giving away his rights, it's more of I could tell by the tone in his voice he was finally really thinking about things and he did concede that it would be best for my son if he signed his rights over a gave me an uncontested divorce. He loves his son but he is an addict in recovery and is not stable. So do you think my family is right to call him a sorry piece of **** excuse for a human being or do you think he needs some compassion for making a tough decision?