It's a toughie
I wouldn't imagine they'd be much point in taking him now in terms of meat you'll get in return (could be wrong though) and if you're seperating them it's best to be out of sight and smell of the other, which in effect means you have 2 lone pigs (neither will be very happy and as the weather turns, they'll be cold and miserable without their buddy to snuggle up to) Again, taking him now and keeping your gilt produces the same problem
Unless you can get her another gilt to keep her company
(would be best to be of a similar age/size)
Although it's usually 6 months onwards for sexual maturity, they do tend to get a bit of practice in early on and pigs have a terrible habbit of not reading the same books as us and just doing whatever they feel like
If she's showing any signs of coming into season (ie. she's standing for him and her vulva is red and a bit swollen looking) it's better to get them seperated asap.
HTH ?
Karen x