It's normal to feel scared and overwhelmed. Your son's life will be different with diabetes, but there's no reason he can't have a good life. I've had D since I was 4 and have done well in school, worked busy jobs that required a lot of travel, hiked the Grand Canyon and the Baja Coast of Mexico, have a great marriage, and a non-diabetic son. I haven't always done a good job managing my diabetes or been thrilled to have it, but it hasn't ruined my life either.
When your twins were born you had to be scared and overwhelmed when you first brought them home. But you figured it out and became good parents. Diabetes is like that. You have the basics down now (eat sugar for a low, take insulin daily) and will learn the rest as you go.
Type 1 doesn't have as strong of a genetic link as you might think. When an identical twin developes diabetes his brother only develops diabetes about half the time. More info is available on this American Diabetes Association link. www.diabetes.org/.../genetics-of-diabetes.html
And your son has only a 1 in 17 chance of passing diabetes on to his children.
He will figure out how to tell his friends he has diabetes. I'd usually let my close friends know and tell them to give me a Coke or candy if I started acting weird from a low blood sugar. I never had anyone not want to be my friend of date me because of diabetes. It is good for your son to notify his teachers so they understand if he needs to test or eat in class. A lot of diabetics use 504b plans which is an agreement your family would share with his school that outlines any special needs your son has. www.childrenwithdiabetes.com/504
This forum is a great resource. There are lots of people with diabetes and parents. Take care. -Jenna