My bfs crazy ex is preg, she slept around right after break up

I/we really need legal advice on this matter. We are getting desperate because now the ex (lets call her Callie) is demanding legal child support, just a couple weeks ago they mutally agreed between her xrazy ex bursts, that hed pay 'under the table' money for the baby (if it was his). Now let me get into the history of how we totally doubt its his child. He makes a lot of money, therefore she was planning on taking all he's got. She actually said she wanted to ruin him.
They broke up after a few years together in september 2014. Callie immediately slept with someone (I'm pretty sure she lost her virginity and her first love to my current bf) within a week or two. She then slept with her boss (which she was talking to multipe guys while dating my bf) and then another guy that shortly moved out of state. She was used and she came to my ex that was still not over her a couple months, january or February. They had sex and got back together, she broke up with him a couple weeks later, not long at all is what im getting at. He described the relationship as him always breaking his back to make her happy and she seemed to use him and be a rude woman. She would come home early in the morning and never explain why and what she was doing (they lived together in the end of the relationship) He later discovered that she was basically cheating on him. He never disrespected her, was not a bad bf. And a month after they copulated, she tells him she's pregnant and she tells him its his. The problem with that statement is because he has to take testosterone shots because his body cant, therefore he has low sperm count and very hard to impregnate than a average joe. Somehow the other man says there's no way he got her pregnant.
SO she's trying to pin everything on him. When they were being mutual, she asked and asked to get him to buy baby furniture and he even paid for her medical expense to see a OBY, she doesn't have insurance!
WHY DO I SAY SHES CRAZY? :
She constantly harassed him and a girl he was talking to temporarily and threatened her because she was 'talking to her boyfriend'
she calls in the middle of the night and tells him hes garbage and even told him shed get a abortion (at four/five months pregnant)note: she refused to get a abortion when he asked at the beginning and said she'd raise it, this is manipulation and stupid of her.
She's made fake social accounts to stalk him to see who he's talking to and what he's doing. This is why he cant mention me or tell anyone except in person that hes dating me for almost two months seriously.
He knew if he pissed her off, shes trigger happy apparently, shed demand all his money, especially if she knew about me or if i confronted her.

He says he's talked to lawyers or whatever that say that women always win when there is a dispute over child support (she doesn't even work since shes been pregnant and lives with her dad thats rich) even if shes a vindictive crazy woman that is more than likely using the child as a way to ruin him. Can't he just give up his parental rights to not pay Callie the money the judge wants him to pay???
He is a honest and sweet person, he made a mistake, he shouldn't be punished for being blind in love, it was a toxic relationship. I only post this because i feel like its really a last resort and I can't ask anyone i know in person, they would just judge and have no idea, the situation is so confusing and crazy. I'm so upset that this is going to disrupt our relationship and his livelihood over a child that may not even be his.

A DNA test will need to be done. If the child is his (might not be), he will be responsible for child support.

I know, but she's demanding she pay for her bills and necessities now. If he doesn't do it, she will make up her mind again to make him pay for the child

He has no legal obligation to do anything until a court orders so

He doesn't have to pay anything until it is determined he is the father & the court orders him to pay child support.

But if the child is proven to be his, it doesn't matter how "crazy" she is or how sweet he is. If he's the father he should support the child.

He doesn't owe her a dime until after baby is born and paternity has been established. If after baby is born and it is determined to be his, it will not matter how "crazy" she is or if she slept with and entire football team, he will owe support for that child and will be entitled to ask for reasonable visitation/custody. If it is not his child, he doesn't have to pay anything toward support and is free to never sleep with, or speak to him again.

You have been dating him for 2 months. You have less than zero standing or say in anything that happens between the two. This is strictly between the two of them, and the child if his. No, he can not "get out" of his parental obligations if it is his child. If he didn't want to father a child, there are many ways to prevent that from happening, including not jumping into bed with someone who is unstable. Regardless, she isn't going to get "everything", but the child will entitled to support from the father until he or she is at least 18.

This is not your concern its his and the Mother to be. If he has money as you say he can afford a lawyer to protect his assets. He owes ZERO until a court says otherwise! If the child is his he will be ordered to pay support. How much depends on many factors however there are countless child support calculators online one could use to gauge that. Why is this such a concern of yours? You have been dating this man a short time.