It is important to recognise that with Type 1, you do become your own expert on the condition. In time, you can become so much of an expert that you can easily develop a poor attitude towards the involvement of medics. My own experience is that your average GP could write their knowledge of Type 1 on a fag packet - whereas your average diabetic could write an encyclopaedia on the subject!
All you need to do is to love and support him. Never criticise his control or sit in judgment over his actions, but be sure to ask him how he would like you to support him i.e. for him to tell you what helps and what annoys!