Father of Son(my ex) arrested last Friday, need custody advice.?

I was with my ex from March '07, until March of '09, during which time we had a son in Jan. '09. I left him in March 09, due to his extreme partying and drug use. There was a huge fight and the cops escorted me and my son out, and I moved into a 3 bedroom trailer that I rent from my parents. Right after we left, my ex went back to Ontario for 4 months, and during this time we did not hear from him. When he came back, I allowed visitation and we eventually got back together for about 3 months, until I found drugs in his bathroom and we broke up. This was July 2011. He has since not seen our son, except on MSN once about 4 months ago. He hasn't called or attempted to contact us in about 4 months. Last Friday, my ex was arrested and charged with Possession of $15 000 worth of Cocaine and some Marijuana. His trial is next week. In Spetember of 2008 he was charged with possession of Ecstacy. He has priors in Ontario for assault causing bodily harm and posession of illegal weapons. He also had a warrant in our town for an unrelated charge, and he still has an outstanding warrant from Ontario from 2007. He also spent 8 months in the Penetang Superprison in 2007, before I met him. My question is, would I be able to file for sole custody while he is going through his court process? Do you think he will be in jail for some time? It's not that I'm being spiteful, I could honestly care less about child support (which I have never received). It's more that I wish to be able to make all the decisions for our son if he is in jail for a while. And I want to be able to travel with our son without needing written permission from my ex. I would also like the add my last name onto our son's name. If you could give me any opinions or advice I would appreciate it. Thank you.