Bf hasn't don't taxes in 10 years

So basically when I met my bf 8 years ago he told me he hadn't done his taxes since he left his ex wife cause she had messed around with some things. Honestly, he is a permanent resident and just doesn't understand alot when it comes to the government. I had been on him for awhile about getting caught up but eventually gave up and filed it away as not my problem. We share a child but we have never lived together for primarily this reason, this type of stuff would make me loose sleep if we were connected financially.

Anyhow he recently started working for a new employer that wants him to open a gst account. He is a contract painter that previously worked for the same guy for 15 years with absolutely no deductions taken off, just straight cheques. I did notice when he gave me papers of his before when we were looking at doing his taxes that he has a previous gst number set up by his ex. I'm assuming this is why he had some revenue canada mail stating a balance owing when we first met. He never paid btw and I gave up on helping him for lack of his follow thru.

So my question here is where to even begin? He thinks he is just going to go to city hall and get a gst number but common sense tells me that won't go as he plans. Really I want to know where I can send him to talk to someone that will tell him what to do cause I don't have the patience to sort any of this stuff out. And will he be able to claim bankruptcy on taxes owed? I feel like he going to be well over 100k...ughh such a hot mess but thankfully not my mess lol

Thanks for listening and any suggestions you can provide.