Proudable doesn't exist at all, I'm afraid - it's a complete nonsense word. Nonsense words can't have synonyms, because they don't mean anything!
Prideworthy doesn't exist either, but at least we have some idea what you are thinking of. There are some ideas which can't be translated by single words.
I would express this idea in a phrase such as:
He deserves to be proud if himself.
Would that be suitable for what you want to say?