And I've just realised seconds after the edit timer expired that he's not going to be able to do that with a broken arm is he... Nonetheless he should pay for the damage if he's old enough

It would be better punishment to make him do work with the one good arm.

And then earn some money on top by entering him into an arm wrestling competition come Spring.

do you call this a small problem ?

It's a small problem compared to the possibility of OP's son accidentally killing himself.

#5 she didn't call it a small problem, not sure where you got that from but there are worse things one can get than a broken arm by falling

#5 Yes, it is a small problem compared to the other options of what could have happened: Hitting the angle wrong and becoming a paraplegic, quadriplegic, breaking his neck and dying, hitting his head and falling into a coma, hitting his head and having permanent brain damage that causes mental retardation, or gives him severe memory loss and he can't retain new information without being told umpteen times. And that's just the things I can think of off the top of my head.

"Off the top of my head" I see what you did there

I mean, a broken arm heals eventually...

People heal naturally, vehicles dont. Im care more about my instruments safety than mine.

Yes because he really expected his son to go flying into a fucking truck and break a limb during a snowstorm.