The best thing you can do is encourage him to move out of home. Of course he's not motivated to earn big money - he doesn't need to!!
If Mummy is looking after him, even buying tickets for him and asking his boss for time off... you're doing too much for him. He's got it easy. Why does he need to exert himself?
I was living on my own at his age. Money was short and I was young... but you learn valuable lessons that stay with you for life.
And isn't that the goal for every parent - to raise a confident, able person who has a successful adulthood? So why are you still babying him? Perhaps you need to look at your own issues before you worry about his.