Hi!
The little baby in my avatar picture on the left is the legacy of a supposedly safe over 5 weeks post-op boar (not one of mine, I hasten to add). But Tegan (now nearly 8 years old) is living proof that can really happen as late as that - and like a lottery win, it can happen to anybody because you are playing statistics. Why go to all the effort and the cost if you put it then all at risk by reintroducing them too early?
For the time being, your boy can live in an adjoining cage to your sow as long as he cannot climb, jump or wiggle out. Be aware that boars can be amazingly athletic and determined if a sow is in season! This will keep the bond live as long as they can interact and see each other through the bars.
You can find more information in neutered boars and neutering operation (including what possible complications to look out for) in this link here:
Neutered / De-sexed Boars And Neutering Operations: Myths, Facts and Post-op Care
Please take the time to read up on pregnancy information and baby care via this link here. A good balanced hay based general diet is key, as is not overfeeding and not overloading the diet with too many extras since the actual amounts are only very small.
If your sow is turning out to be not pregnant, being as healthy and fit as can be, won't her hurt her any!
You can access our comprehensive information, which has been specifically written for owners facing an unplanned pregnancy or surprise babies without experience, via this link here:
Pregnancy & Baby Care Guide's