I mean, no, if you have full custody he can’t legally do anything, but he sounds like a jerk and maybe abusive so I think before you do anything you really need to work out a plan with people who know about these things. You should contact an organization for women who need protection from domestic abuse and work through a plan to get away from your ex safely.
The other thing is you have to have a safe and secure place to take your son. And if you’re struggling mentally you need to get help. So I urge you to contact a women’s organization and find out what resources are available to you and how to safely extricate yourself and your son out of this home and into a safe one.