I want my 3 yr old to lose weight

I Have a 3 year old son in the past 8 months he has put on 6 kilos, he is 100cm tall and weighs 23 kilos.  He has severe asthma and since he has been put on more asthma medication and has not been able to run around he has put on a lot of weight.  At 2 years and 4 months he weighed 16.5kg which was in the normal weight range.  He is a very Tall boy but we have weight problems in my family and I wnat him to lose the weight now so he won't end up a fat kid at school, and also for his health.  I am very worried and would like him to lose at least 5 kilos.  is this possible?

[CHELLETO6DOGS]

this might not be easy especially is he is on any type of steroids, which can do this to you.
If it is allowed from your insurance I wold ask his doctor to go see a dietitian to help him. I think you already know to give him healthy foods and on and on. but sometimes it is harder for a child to loose weight die to a medical condition or genetics,
good luck and I hope he can do it