My son was like that at that age... I would just put him on the potty, with a diaper on or not... (per his comfort with it), and he would sit there when I was sitting on the toilet too, and sometimes he would make pee, even if it was in his diaper while sitting on the potty chair. Hooray! Then I would high five him and cheer him! And he would tell me whenever he was about to pee, or actually just peed' (in his diaper), and holding his thingy.
Or I would leave his diaper off during the day when I was home, and put the potty chair right there... and he would go sit on it sometimes and actually pee. Or sometimes not and pee on the floor. But it's okay.
Main thing is I went according to his comfort level. But he could indicate to me when he needed to pee, and would go sit on the potty chair. Most of the time.
Then he is now going through a phase in which he does NOT like the potty, and refuses to take off his diaper. So, I don't push it. He only just made 2 years old, so that's fine, to me.
He gets kinda "possessive" over his diaper nowadays... and HE wants to decide when to take it off. LOL. So well... as usual, it fluctuates. But no, I don't think of him as "potty trained" per say. But he has been interested on his own before 2 years old. So that's good.
But, go with it... since your son is "interested." But don't push. Keep him positive about it. That's GREAT! Keeping in mind it ebbs and flows and success goes in spurts....
Just try and keep consistent...
Good luck!
Susan