As usage (He taught all he knew to me, as a father would to a son.)

[navi]

Are these sentences correct:
1-He taught all he knew to me, as a father would to a son.
2-He taught all he knew to me, as a father does to a son.
3-He taught all he knew to me, like a father to a son.
MEANING OF 1, 2 AND 3: He did the same thing that a father does for his son: he taught me all he knew.

4-He taught all he knew to me as a father would to a son.
5-He taught all he knew to me as a father does to a son.
6-He taught all he knew to me like a father to a son.
MEANING OF 4, 5 AND 6: He taught me all he knew in the same manner a father would teach all he knew to his son.

[Haihao]

1: the best; 6: the best, I think.

[Jamie (K)]

I don't think the comma makes any difference in the meaning of those sentences.

[Haihao]

[Jamie (K)]

[Haihao]

I am sorry but it seems to me that navi set up an assumption on 1,2,3 with the 1st meaning and 4,5,6 with the 2nd. Of course the comma, as you said, makes no sense here, with or without.