I don't know, is this important

My friend, (uses they/them pronouns) who is now 15 but will turn 16 in March, just told me a few days ago that they started dating a 12 year old girl, who will turn 13 this year. They haven't been together for long but they already had sex and talk about sex very often. They are, i think, both hypersexual, but still, it doesn't sit right with me. I don't really support this kind of relationships but i don't know, am i being too dramatic? Should continue being friends with them? Should i just tell them something? Please tell me what you think

Side note: there's no risk of pregnancy, they are both afab (assigned female at birth)