Bony T1 Teen Son

My son was diagnosed 2 years ago and since then he hasn't gained an ounce. Hasn't grown much either so he is the smallest in his class. We are hispanic so we never expected him to be tall but his growth is definitely affected. We have the best doctors, he wears an omnipod pump and his levels are under control. I am looking for a diet that would help get some meat on his bones.

You should probably check with your son's doctor and see if it would help to meet with a dietician.  

If your son's blood sugar ranges are generally okay, diabetes shouldn't affect his growth.  Consistently high A1cs and frequent occurance of ketoacidosis can lead to stunted growth and delayed puberty in some diabetics.  

If your son has the same pediatrician, or if you can get access to his medical records from when he was a toddler, the doctor may have done an estimate of your son's adult height based on his height at age 2.  It would be interesting to see what was predicted and what he is.