ANSWER:
He is your father and he is your gateway to paradise.
He is a grownup man and he is answerable to Allah. It is none of your business what he does in his personal life. Focus on your career and on trying to get married.
Tearing up your certificate and driving a rickshaw is something everyone can do! It would only express your ingratitude to Allah over the many various blessings He had bestowed on you.