@QiaoZiJian,
The art market is very secretive.
In order to get details of how much things went for auction you need to be a member of a trade website.
It costs a huge amount of money to join, it's just not worth it for one or two paintings.
Having said that I googled the name and found one of his paintings for sale on ebay for US$500.
That is whst domeone is selling one for, it may have just gone on the market, or it may have been there for some time.
At the end of the day something is only worth what someone else is willing to pay for it.