I have to say yes. Though my answer is probably bias, because I've been fangirling these two as yaoi. Brian can't hold onto a girl, and has been looking for someone that is intellectual. Stewie we have seen with girls, but we have also seen him liking guys. It would just seem a great match for a couple. They would fight, but what couple hasn't? In my mind, Stewie does l’amour Brian THAT way.
i think so cuz 1.stewie put his thumb in brains mouth and then when brain left stewie started sucking on the same finger that was in brains mouth
2.one time he walked passed brain and his son naked and and said...just passing par see any thing toi like speak up
and he likes brains son cuz stewie was naked and he told the kid to take his f*cken pants off and then he talk to his ours how to loose a man in 10 secondes staring stewie griffen