He needs to learn that actions have consequences, for one, and two, if he has such strong and militant beliefs, what the fuck is he doing asking Mummy to cough up for him to have a mini Gap Yah, anyway?
I knew people like him at uni, and tbh they fucked me off to fuck. They always pontificated on about their fantasy left wing identification before taking up high-paying jobs at ICI, and becoming the Toriest Tories that ever did Tory. Lots went to places like Eton. They were tourists playing at poverty - one little gang even took advantage of a local guy's sympathy for the homeless so they could play at living in a squat. You can imagine his delight when he discovered that the "homeless" kids in fact inhabited an Oxbridge college in term, and very nice parental homes in the holidays. Pretty cut-glass, under the mockney. He'll never seek to help homeless kids again. Nice work, brats.
I grew up with a disabled sibling in a housing association flat with a single mother. Kids like your son still make me angry. Tell him to listen to Pulp's Common People, because everyone does, indeed, hate a tourist. Pointless bourgeois materialism would include poncey, parentally-funded, didgereedoo-accompanied road trips - and tell him to look up the Aboriginal position on cultural appropriation while he's at it, if he's quite this keen on checking privilege. He's not so good at recognising his own, is he?
And for the record, poor household or not, I was brought up to value the feelings of others. It doesn't matter what he broke. You loved it, and he destroyed it. He has to be an adult and face the realities. That means going without something he wants, because money - even Mummy's money - does not grow on trees, and you put right your mistakes. Especially chosen ones.