Without a EU passport he's got next to no chance of finding anything in Europe. While there are companies that are able to get visas for their staff, these tend to be experienced managers, instructors, chefs etc. rather than staff with no experience and no relevent qualifications.
If you look at the recruitment sites for the major British tour operators (Crystal, TUI, Inghams, Nielsen etc) they all specify EU passport holders only - and since Covid/Brexit most of the TO's "British" resort staff either have Irish passports or have a EU passport through a foreign parent. I've met several "British" reps who were born and raised in the UK, but who have a Dutch, French or Scandinavian parent and so have dual UK-EU citizenship. To the pp^ who thinks that this is early for TOs to be recruiting, the opposite is the case - recruitment starts in July and much of their recruitment will already have been completed.
As for finding casual work and somewhere cheap to live - these are both very difficult to find. Few employers are willing to take on someone "off the books" as the penalties are huge (just as they are in the UK) and accommodation in resorts is scarce and expensive. Remember too that if he gets caught, the penalty might include being deported and banned from the EU/Schengen countries for a number of years.
Ski instructing is not an option as he'll still need a work visa (which for a first-season instructor is almost certainly not going to happen).
There are however still some options available. If he saves enough money between now and January he could just be a ski-bum for 6 weeks, skiing every day without needing to work.
Or he could go to a non-EU country - the most obvious being Andorra.
Or as others have suggested, look at Canada. He'll need a Working Holiday Visa These visas are limited in number and tend to be over-subscribed, and he may well already be too late for the 2025-26 season > International Experience Canada: Who can apply - Canada.ca