male and female herd

I have been offered a neutered male guinea pig (age 1.5) to add to my herd of 4 female guinea pigs ( age 1, 2, 3 and 6). I have to get back to the person offering him to me by Monday. He got 2 neutered males off the DSPCA but one recently died and the other is now on his own. We have a large C&C...