parents' trouble with kid's homework

I don't know if other parents face the same issue, I am getting swamped with coaching my son's work. He attends private school (KG). A whole day school will train him on reading, math, handwriting, drawing, art and gymnastics. I have to coach him on Chinese and piano at night, plus review his homework. He doesn't like Chinese and piano as much so it is hard to have him sit still for those. The day before yesterday, he worked on one page of Chinese. It took me an hour to get him finish. Then we read his school books. Then he wanted to finish his drawing. When we are done, it is already 10PM. We haven't got to do piano. I also worry that it is too late for him to sleep. Then yesterday night, we did piano theory for 40 minutes since he doesn't like to practice, then math for 15 minuts, then reading for 20 minutes, then drawing for 40 minutes. No time for Chinese. Time to sleep is also 10PM. I found that he only work on Chiese or piano when he feels fun or play. I need to desigh a game to keep him interested. It is challenging to do that all the time. I also noticed that he is more interested in school works instead of the work I added for him. He knows he needs to finish school works so he can get appraise. I am not sure if I have added too much for him. But Chinese and piano are important to do on daily basis. It is also a hard commitment I have to make. Staying with him every night at home. I don't know how other parents handle it. I can't imagine to have 2+ kids...