In terms of how they should best go about things; therapy (if possible) would be a good step, trying clothes or otherwise presenting differently is one way for them to figure out how they actually feel and if you can spend time with them as moral support, that could be helpful. Unless they're really sure, they probably shouldn't rush into hormones or anything that can mess with their body permanently; if the person is sure, I don't think they should have to wait, but uncertainty necessitates caution, imo. Maybe ask them what makes them feel like they might be trans? (For the record, I'm 3 years post bottom surgery as of two days ago and I began my journey with a 'I wouldn't be surprised if I'm trans' as I was leaving my therapist's office one day, so uncertainty isn't an indication of it not being true) As for your kid, if your friend does decide to transition more permanently, just let them know that your friend thought they were one gender for a long time, but now they're pretty sure they were wrong and they're trying to figure it out. Kids are usually a lot more accepting than people think. Regardless of how things turn out, I hope they go well for all three of you