Well, the bottom line is that if Dad wants to eventually file for visitation he'll likely get it.

As aardvarc said, it would likely be a graduated visitation schedule at first, eventually leading up to longer periods, overnights, weekends and full weeks during the summer.

Sorry, but that's the reality of the situation. LA has no SOL in establishing paternity when there is no presumed father, so Dad has up until your son's 18th birthday (and sometimes longer) to do so.