[quote tripodd]@Justkeeppedaling as stated above, he is 18, so not a 'child' and has a coaching qualification, dbs, also a first aid certificate. He has lots of volunteering (and playing) experience already.
But actually I'm not after opinions on whether he takes the role - that is up to him - I want him to make sure the role is properly defined, and not breaking HMRC rules, and I also need to decide whether to mention anything (gently) to the club.
Thanks for your help everyone. I will try to work out if some of the full coaches are self employed, but most of them do have 'day jobs', e.g. as teachers.[/quote]
Just drop it. You're being over pedantic, and worse case you'll affect the future of the club, which probably relies heavily on people like your DS doing a bit of informal volunteering for expenses.
You're also being over protective of your adult son, Let him mane his own mind up, and learn a lesson from it if he makes a wrong decision. At 18, I would have been absolutely mortified if my mother demanded a copy of my job description from anyone I was volunteering or working for.
The club will probably refuse to give it to you anyway as DS is an adult.