At Disneyland Hotel there's Minnie Club Playroom. It is a free club for children aged 4-11 years but they can only be left for one hour with the trained supervisors unless a parent / guardian / babysitter stays as well. They have toys, drawing, and play games. You can book a babysitter in advance, which costs 30€ per hour, for a minimum of 3 hours (extra charge on Sundays and Bank Holidays). The hotel uses qualified babysitters who come from Paris, they don't have their own Disney babysitters. The babysitter would look after the child in your room, or in Minnie's Club. Minnie's Club is near the swimming pool, and is open from 2pm - 9pm.
As for birthday surprises, you can contact DLP.DISNEY.SPECIAL.ACTIVITIES@disney.com and have a birthday package arranged to be delivered at your room on your boy's birthday. You let them know what items you would like to be included and they give you a price.
