Looking for book where space man human helps aliens

I just got done reading Cat Country by Lao She. It's a satire tragedy where a man goes to Mars and witnesses the collapse of a cat people civilization. This is a tragedy so there's nothing the protagonist could do, but throughout the book he wishes he could do something, anything to help them but can't.

I kinda want to read a book where the idea is similar (man goes to alien planet or other world) but he actually helps out the aliens/nonhuman with their problems and makes friends and bonds and such.