english classes for kids

Not sure if the BCT in anything they used to do play grounds for similar children check out their website. http://bctbelgium.org
Also never too young to join the waiting list for British scouts beaver start at five and a half with beavers but tends to be an evening event.
http://www.1stbrussels.be

Yes, use google and search for activities.

At this stage I really wouldn't worry with extra English classes. My 3 grandchildren are all bi-lingual (Dutch/English). At a young age they understood both languages but mainly used Dutch. The two oldest now 7 & 4 years old switch between Dutch & English depending on who they are talking to, the youngest aged 18 months is still learning but understands everything in both languages. The use of English will come when your child is ready, just continue to speak to him in English to develop his vocabulary.