I could have lived like this when younger. The only thing that would bother me is being cold! Indeed we still very much enjoy our touring caravan at age 78 and 73. We have had just two 'vans in 38 years, the first had no mains electric, no hot water, but we managed well without these things going all over the UK and Europe with two small children - and not always on sites with toilet/shower blocks. Stand up washes after boiling a kettle on one of the two gas rings was sufficient. The fridge, heater and two gas rings and a tiny grill (no oven - the pressure cooker did the major cooking) also worked off gas. Later DH fitted mains electric with a kit which gave us electric lighting and the ability to have a telly! We all loved it.
Our "new" van is now 15 and we think it is all-singing, all-dancing, but it still isn't luxury compared to some.
We will be heartbroken when it comes time to abandon our home-on-wheels and I'm looking into a second-hand campervan!
But then I lived the first 5 years of my life in a one-up-one-down with no toilet (there were two in a ramshackle building down the yard, shared by 14 houses - we had jerries in the house!) and a gas boiler for washing in a tin bath once a week. All was fine for us and I remember being very happy there. When we moved to a 2-up, 2-down with a bathroom and electricity my mum was over the moon!
As others have said, the young man may not earn enough to pay tax (and why should he not? - loads of people don't pay tax due to having low incomes). Of course he WILL be paying tax on vehicle tax and VAT/duties on fuel, and other things he buys to live on, perhaps not basic food but clothing, equipment etc. Good luck to him I say.