[mistwang]

Yes, you can configure Apache with it reverse-proxy feature to forward everything to LiteSpeed on that domain. It is pretty easy to do, please consult Apache's manual.

However, it is not a optimal solution and you will get much less benefit than using LiteSpeed directly. With LiteSpeed's built-in watch-dog feature, there is not much need for additional monitoring work.

If that server has multiple IP addresses and that domain got its dedicated IP, you can let LiteSpeed bind to that IP on port 80 to serve that domain directly, the other sites can still be served by Apache. If the site owner is happy with the results, more sites can be converted later on.