Floundering, in answer to your question what you would do, I'm answering from the perspective of having teenagers.
If someone is suicidal, it is primarily a situation of helping them. I would get specialist help and therapy for them, and yes, I would support them to have surgery if they were an older teenager and they had been through a therapeutic process.
I would not be happy with puberty blockers because it is going through puberty that allows someone to have a better understanding of their identity and sexual orientation, and I think that understanding is necessary to make an irreversible decision. But then that is easier for me to say because both my teens have a fairly androgynous physical appearance so there would be fewer 'passing' consequences - height, bone structure etc if they did turn out to be trans as adults.
Having said that, many people make decisions that irreversibly change our lives (sometimes for the worse) as young people, and sometimes that is better than the psychological damage of controlling parents stopping them from making that decision.
I'd also make sure they had plenty of gender variant adults who were not trans to talk to (as they already do) so that they had a good range of experiences and role models to draw upon.
That is because I wouldn't want them to get drawn into this notion that most people have a gender identity and that most people have gender experiences that align with their sex, which I think young people are exposed to by both consumerism and trans blogs. I think that is important whether or not they are trans as an adult, because otherwise they might end up with an unrealistic expectation of what being an adult man or woman 'feels' like, against which they may measure themselves and be distressed by.
I also think part of bringing in role models is because I would try and not control the process my child was growing through. We don't know what causes these strong trans feelings, so I can only use as my guide other body and identity issues. Many body issues are partly caused by and exacerbated by feeling that others are controlling you and what you do with your body, and I would not want to add to that. Teenagers experience identity differently to adults. Even if a teen is just something like an emo, at that moment in time it really is intensely who they are, and challenging or dismissing teen identities can be very damaging. So whatever their identity, be it about gender or something else, I would seek to respect it, however long or short lived it was.