They should be fine. Don't panic unnecessarily. It seems you have a contrast of personalities, which is good. I've had pigs that have sailed through the adolescent stage - which ends around the year mark - and others who have had a rockier road, with rumbling and sniping. One particular pair continued that way for the rest of their days together, but if you took one away, the other would be searching for his friend! Sometimes with boars, it can be a very love/hate relationship, but seeing as you have a laid back boy, things should all fall into place pretty well. Just make sure they have two hideys, so they can get away from each other if they want to. What size accommodation are they in?