Here's what you can do for him

• Love him
  You do that already otherwise you wouldn't be reading this
• Don't try to change him, he will become even more silent
• Try to listen to him even if you don't really understand what he tries to tell you
  Perhaps he doesn't know yet either but he tries, believe me he does
• Make him feel that you are simply there for him, with patience and all the love you can give