Can he find a "no win no fee" lawyer? Is there a blue collar trade union he can join which provides legal help? Are there any legal aid organisations in your town?
It seems worth doing a bit of digging around advice organisations to get opinions/ referrals, since from what you say he should have a good case. I know it's triggering to not have the money that you need to solve the problem of not having the money, & etc - but that is what trade unions and advice organisations are there to provide.

Even, I once got great advice from a debt counselling organisation that happened to have someone with legal experience on board. I called a heap of supposed debt advice people who were useless, then I chanced on a well-informed place.

It's worth trying everything you can find, and then some. Good luck!!!