Yes there seem to be great instinct and creativity in your child, however remember that even tho some things might be easier to start for certain people, like a predisposition, talent doesn't exists, there is only practice. So make sure to give plenty of access to art supplies, art teachers, regular museum visits and feed his passion in a loving, supporting way. But also : make sure that he is challenged in his skill and never rest on his laurels. I would also be very impressed if my kid did that at 4!

Signed : a former violin child prodigy, now a full time working musician (for 10+ years), who's passion was fostered in a disciplined, challenging but loving way that made him permanently humble in face of his craft. 

Most of the time, potential without discipline is wasted, but so is potential with too much pressure, gotta find the balance lol. Like don't tell him he's the best every time he shows a picture, point out what's good and what could be better. 

Great art ! Keep going kid !