Some preschools don't take them until 3 so he may not start until next January so that's probably something you should ask.
Do they provide fruit, do they charge for it or do you have to provide your own.
Do they have free access to a drink or is there a specified snack and drink time.
How many children are in the class and how many qualified staff/volunteers.
Do they do any PE, computer based learning, singing etc?
Do they go outside every day? Are the children able to access the outside play area at all times or is there a set time when they go out there.
Do they ever make cakes etc?
On their first day do they do a split session so half go for the first hour and half go for the second hour or do they all go for the whole session?
Is it mostly free play or structured activities.
Do they do any teaching of phonics, reading or writing?
Do they have to wear a uniform?
Just a few to get you going