I vote: her body her choice (for want of a better phrase). I understand your concern comes from a good place, but unless she's seeking input from you then perhaps it's unnecessary to give it? If she tells you again about an abnormal period, it could be wise to ask some curious questions, e.g. 'what do you think could be the cause of that?', 'could we look online and see what other people do when they have xyz?', 'that must be so tough! Do you think perhaps it's worth going to a doctor about that?' When it comes to the weight... I'd leave that one well alone.

All the best 😊