Most men are tense (present), some men have been tense (past) and got over it, and a lot of men will become tense (future), however man, as a noun, which he is, and as Homo Sapien, could possibly have been Homo Erectus (his past) but yet still a man.
Therefore there is no past tense of man except a previous man, and by conclusion "father" i.e. his father is his direct past.
Man is a noun, as rightly stated by all others answers.
However, to father, is a verb, which can have a past, which is to not father or to be childless.