Hello! My family is staying in Brussels for 2 weeks and we would like to hire a private guide in the city and also to possibly tour some local castles. We have two kids ages 9 and 6. We plan to take day trips as well, but we find a local guide can really introduce a city. Thanks in advance!
Not a direct answer to your question, but just so you're aware, Belgium only has a few examples of what most people think of as a "castle". What might be dubbed a "kasteel" or "chateau" in the local languages could usually be better described in English as a "mansion". Ghent has the only example of which I'm aware of a medieval-style castle, and even this is largely rebuilt. There's a few old citadels scattered around the country, and perhaps these could loosely be described as castles.