Is this delayed puberty?

[noarguments]

DS is 20. He has been a year or so behind his peers with most things.
He's shot up in height in the last five years but he's not changed shape iykwim, he very slim. Obvs I have no idea what's going on "below" but he has no underarm or facial hair whatsoever. He doesn't have body odour.
Is this normal? I've not spoken to him about it but feel like I should in case he's worrying (he's a bit of s worrier). I wonder whether he ought to get his hormones checked out..? Would you be worried?
Thanks for any advice.

If it were my ds, I’d be right down the GP, tbh. 20 seems very late. Has his voice broken?

Yes, see the GP as a priority

I would urge him to see the doctor. I know boys all develop at different stages though. My son is 13 and has a deep voice and facial and body hair, size 11 feet. Some of his friends only look about 9. But by 20, I'm not a doctor but he should be done with puberty.

Encourage him to see the GP as a referral to endocrinology sounds appropriate.

Hormones involved in puberty are also important for health reasons so if he genuinely hasn't gone through puberty he may well need medication

2 weeks on.... GP visit and blood tests reveal low testosterone so he has referral to endocrinology. I feel stupid for not making it happen sooner now. Trying not to google the potential causes, hoping for a short wait for an appointment. Also hoping he'll let one of us in with him, he didn't want us with him at the GP appointment but I'd worry he won't ask the right questions or remember the detail if he's just there on his own.
Anyway thank you for the advice.

I could see not being in the exam but I hope that you were Abe to ask questions. My sisters and I were 16 when puberty started. Turned out ok. I’m sure they’ll be able to solve it. Good luck