My DD was totally potty trained at 14 mos. We had to hold her on the toilet b/c she would have fallen in. It wasn't great for us b/c her bladder was the size of a pea and we were always running to a bathroom. This was her iniciative. She had amoebas when she was about 12 mos old and I was putting her on the potty to avoid having to wash the diapers. She decided she'd rather go in the potty after that.
I think it is fine to potty train him. You're just following his lead. My little boy is the same age and shows no signs of readiness. He's more interested in playing in the toilet. (I found his toothbrush there yesterday). But if your little man seems ready, I say go for it and keep it really low key. Take him to the bathroom when he has to go but don't put any pressure on him to do it. See what he does. If it doesn't work just let it go and try again in a few months.
Good luck!