Yes. His responsibility as new parent. If he was man enough to bring someone into this world, he should be man enough to stay and be there for them.
Are they happy together? If so it's a happy ending.
Short answer no. Long answer Nooooooooooooo.
after seeing what my niece has done I'd say no, sorry for the baby but some women just trap a man and set them up for life to be their slaves using the child as a tool to do that
No, he should run like mad :)
No. Only if he loves her and wants to spend his life with her. :)