Hi Nicola,
Things will get better, you will get more used to things, you will get used to a new kind of 'normal'. You are on a very steep learning curve now and it is exhausting, and because (like me) you go all out to find all the info you can, it is even more exhausting and worrying. I know it's easy to say and hard to do, but try to take things just one day at a time now. Your son will get used to his jabs etc, though I have to say that even after 5 years, my 7 yr old still cries sometimes and regularly has a good old moan.
As far as eyes go, I was told by an eye consultant that they don't normally expect to find changes in the eyes of Type 1 children for at least 5-6 years, and not even then provided blood glucose levels have not been left to run completely uncontrolled.
As for siblings, I believe their chances of developing Type 1 are slightly increased but not much (less than 10% I seem to recall, but don't quote me on that!). You know the signs and can do a test if you feel you have to. I have 2 daughters who are Type 1 (age 7 & 14) - nobody knows why, we have just been very unlucky I think :? . Mind you, there are worse things for a child to get!!
It's good that your son was diagnosed before he became really ill with ketoacidosis which happens to so many children.
Anyway, welcome to the forum and ask away with any questions, somebody will always try and help.
Regards,
Sue