WWYD - Follow up to my post before about bd leaving

So since he has left we have met up yesterday and today yesterday he was very verbally abusive when talking to me and said some extremely hurtful things. Now today when he comes to talk to me he is being super nice and so I look down to see his phone recording me! I immediately start recording on my phone so he cannot twist any more of the conversation. He is extremely mentally unstable and is not getting proper help. He starts asking to have my son without me around and I told him I would think about it and get back to him. He has never shown even when he did live here that he could take care of our son on his own. I am scared that if I tell him no he will find a way to use that against me if he takes me to court. I don't know what to do at this point... he is mentally unwell and I do not feel comfortable with him having my son without me around. Not to mention he wants to take him to his mom's house where he's never been before and would be with people he doesn't know and there are 2 dogs there that are a danger to my son