What would be a good way to convince boyfriend that diabetes is serious ..?

Let him know: That diabetes is the leading cause for blindness, kidney failure requiring dialysis, non traumatic amputations of the feet/legs in the us. It is also a major cardiovascular risk factor, equivalent to someone who has had a heart attack already. It is a major cause for ed. If this doesn't help, take him to a dialysis center so he can talk to patients there with diabetes, see patients at va hospital.