Can I keep my son from my soon to be ex if I fear my ex is mentally unstable?

I files for divorce 6months ago and currently have my son 95% of the time. We have not come to an agreement on custody and out of the 4times we were supposed to go to court he's showed up only once which the judge said put him in default. (he missed our mediation and counseling which both the mediator and counselor recommended I have sole legal and physical custody and he see our son every other sat and sun) our final trial date is at the end of July. I have been letting my soon to be ex see our son every other weekend (mind you, up until our divorce began he was rarely around and even left for three months stating he didn't want to raise our son without me and was to depressed to stay in MI so was moving to FL which I later found out was actually St Thomas VI to be with an ex girlfriend who then kicked him out for his excessive drinking) this past few days I have come across information about how at that time he had told numerous people that he wanted to take our son with him to st Thomas because then he wouldn't have to give him back to me as they have no laws there forcing him to, I also found out that he has been drinking and driving and was heavily involved in drugs last year (we have been separated for 2years) I found this out via Facebook messages he sent to an ex girlfriend. He has also put as Facebook statuses how he feels sex should be an Olympic sport that people get paid for it why not make it a sport and he would participate for sure. He's sent many many many messages to an ex girlfriend stating that he wants to die. When I moved his stuff out I found steroids needles and syringes in his procession. I am starting to believe he is getting heavily into steroids and this worries me concerning the fact my son is around him. I have decided in the best interest of my son and in light of the things I have read and heard from witnesses that I should keep my son from him until I am able to present the evidence I have to the judge on our final trial date. Again there is no current custody order in place only a letter of recommendation from the court appointed counselor stating that I should get sole physical and legal custody. Will I get in trouble if I keep my son from him if I feel he could be in danger until our court date?