If she is unfit, she wont be saving any money as she isn't looking after him & if she is struggling with an out of control son, this fine is just going to make matters worse.
I don't think many people have a clue about how disturbed some children can be, no matter what the parent does.
I don't have access as to what the dynamic here is but its clearly not working, she either needs help with him or, as a last resort, he needs to go into care but that, given the state of childrens services, isn't ideal.
I look back on my brothers childhood, nowadays she'd have fined or indeed imprisoned for his truancy, maybe even care, but she couldn't control him, he would jump out the bedroom window, walk to school but then go fishing, hide his bike by the 2nd bus stop, get off (having been escorted to the bus stop) and then go for a bike ride, if he went to school, he'd then walk out after an hour, he went a total of 12 days in the entire 4th form, less in 5th year, left school with not even a CSE.
BUT he went on to be an engineer, working all over the world, had he been put into care, he'd probably have ended up in prison.
There also seems to be zero mention of the father in all of this.
Decent parents don't need reminding that they should act responsibly, with pointless fines.