DS 18 has 'met' someone online and is a completely different person

[CandyflossKid]

Just as the title says really, DS has apparently joined the dating app Bumble (I'd never heard of it so had to google)
He's 18, lives at home, he's at college, says he's going to get a part time job but hasn't yet, and now is talking to a girl he met online for hours.
He has completely withdrawn into himself and is not interested in his family at all (I know all teenagers are like that) but this girl seems to have some hold over him.
We are not sure how to approach it or what to do.
Why do they have to grow up?

I’d be all positive about it and encourage him to meet her in real life.

And also to do other things in real life too. Getting a job would be a good way to,start as he’d meet different people.

this girl seems to have some sort of hold over him

Of course she does. He’s infatuated and is going through a process of developing a deep emotional connection with someone. That’s a completely and entirely normal thing to happen in young adulthood.

Didn’t it ever happen to you?

...am i weird to think this seems completely normal? First love is all-consuming. We were all young once.

Get him to invite her over (have they met in RL yet?)

DS is 17, and his life is 90% about his girlfriend , she comes for dinner now about twice a week. Other nights they go out or are at hers.... when apart they chat on their phones!

My advice is to be positive, be happy for him, and tell him she is always welcome. Would that be an option?