What do I say to a friend who Is not happy with himself?

It all depends.. Why are they unhappy with them selfs? Try to see why and help them show them. They are cared for and that they are a great person! If you add more detatils I could help you more.

Everybody has secrets. Be careful if "a secret" is the reason for her unhappy. Sometimes people don't like when others poke in to their lives, but sometimes your friend is wishing for someone who would listen to her heart and share her sorrows and be free. :)