At around 23/24 months Nina went through a huge growth spurt.
Nina will sleep 11-12 hours a night without waking.
I reckon he's getting enough sleep. Each person is different with the amount of sleep they need each night. I know some kids that need 10-12 hours of sleep a night, where others only need 8-10. He'll sleep as much as he needs. If he's asking for bed at 7.30, put him to bed at that time, and see what time he sleeps till.