I want to offer the following words of support. When I was diagnosed there were to my knowledge no medicine based treatments at all. Average life expectancy was teens. I survived. When I was 16 I started nocturnal ventilation, heart meds and steroids. I survived. Ten years later I am still here and the average life expectancy has followed me. The average life expectancy is late 20’s in most cases and often much later. Imagine if I'd started these treatments earlier. These treatments are available for you now. I am sure when this guy’s son reaches his 20’s better treatments will emerge and life expectancy will increase.
All you can do is concentrate on life quality.