and because he didn't need for anyone to testify concerning man; for he himself knew what was in man.

 There is no mention of Joseph. The explanation most probably is that by this time Joseph was dead. It would seem that Joseph died quite soon, and that the reason why Jesus spent eighteen long years in Nazareth was that he had to take upon himself the support of his mother and his family. It was only when his younger brothers and sisters were able to look after themselves that he left home. 