The man's semen can be analyzed in a lab to see the viability of his semen.
Blood type has absolutely nothing to do with being able to reproduce.
Obviously
A young person whose face looks like that of a grown man. I AM A MAN CHILD!!!!!!!!!!!!!!!!!! HAHAHA LOL NOT REALLY WELL I KNOW A MAN CHILD :O HIS NAME IS.............. MAN CHILD
No
No. That is the definition of sterile; "not able to produce children or young"
of course why not
Yes
you get his sperm tested.
no
I believe it just dies off nothing happens
Yes. Blood types do not make parents incompatible.
If he is still able to ejaculate, yes.