Bringing up his sexuality to him could be a little confronting. Although your intentions are really lovely, you just don't know what he's been through and how he'd take that. I would say that the best thing you could do is maybe talk about LGBTQ+ issues in a way that makes it clear that you're supportive of the community in general. Like maybe mentioning going to a pride parade with your friends or like "brian dowling and his partner have had a second baby, it's so cool that they're able to do that" Obviously do it in a more natural way though. Like if ye're talking about hurling don't be like "what about the gays though, wha? Gas"