That is ~11 paintings per day, every single day. There is a girl, who at age 3, can solve a rubik's cube in a minute. I would say it is possible, if guided by parents, but at a cost of social and emotional development.

Assuming he started painting the day he was born.

There are child prodigies, but there are also people making stuff up for fun and profit.

But I'd still love to see a video of his process.

Even if you exclude the first year of his life, that wouldn't change the "~11 a day" estimate by much. It might up it to "~12" a day.

No, but it is hard to tell when did he start. If at age four, that would be still possible with 22 pictures, assuming most pictures are small.