Oleg , welcome to the forum , I'm sure that JTR2006 ,who is far more qualified to provide answers than I'm , will respond soon. I'm a diabetic myself but type 2 , which means I take tablets , watch my diet and exercise .You little boy , bless him , must be type 1 and he is on insulin. The care in Cyprus is as good and better than most European countries. I live in the UK , but always consult a diabetic specialist when I'm in Cyprus , will be pleased to give you his details.
Unfortunately climatic changes are of no relevance to diabetics , but because of the weather he would be more likely to go swimming , play games and generally keep fit which is a must for diabetics. I take it when you say your son is 4,5 years you mean 4 1/2 years old not 45.
Should you want some details of my Doctor in Cyprus you can email me.
Regards