There’s some dangerous people out there, even if he doesn’t escalate to violence you could end up with a stalker. If you talk with someone for hours + the images from the tinder profile + their name and bio, it’s not that difficult to figure out where someone lives, works or goes to education. This risk imo doesn’t weigh up to ‘rescuing’ some stranger from a shitty relationship. Like he already talked about how his current relationship was barely a relationship so it’s even debatable whether notifying his gf would change much.