Try calling a local psychiatric unit and ask for their procedures on committing someone who may be a danger to themself or others. GO to court and prove that he is a danger to himself and others. Get a court order committing him. If he gets arrested, ask that the court commit him in lieu of prison.
Parents should remember 3 things: Love your kids more than you hate your ex; when you have children the relationship with the other parent is until death; your children determine what type of nursing home you end up in.
Nothing stated by me should be taken as giving you legal advice or forming an attorney/client relationship.
Attorney-GAL in Ohio.
I've removed the knife from my back, polished it, and will one day return it -- long after you think I have forgotten.