I hope neurodevelopmental disorders would also get more attention. Although less people suffer from it than from aging-related disorders, when a child is born with a severe disease it affects not only the child’s life, but also that of parents and siblings. (I don’t mean neurodivergence, I mean severe disorders that prevent a child from being able to walk, communicate, and/or live in health).
In comparison with aging-disorders, so many good years of life are lost.
I had a similar experience during a three-week cold, but in my case once I started vomiting I kept vomiting up slime until two days later I got some medication to calm my stomach. Had a mild scare because of chest pain right after, but it turned out to be an inflamed ribcage from all the coughing and vomiting.
I finally realised I kept having recurring colds because I had silent acid reflux, without any symptoms of acid reflux. After 8 months of getting sick every 2 months and staying sick for weeks every time, I started a diet against reflux and so far I have not been sick yet (4.5 months later).
In metric: he is around 1.82m and 65 kilos which puts him at a bmi of 19.7, which is at the lower end of a healthy range.
As a beginner doing anything is better than doing nothing, so why not just be supportive and offer to help/explain stuff but don’t give unprompted advice. There is so much you can already achieve with some weights at home and he doesn’t have to go full gymbro to see meaningful changes for health and fitness
As for the diet, maybe send some nice recipes, but don’t push it either.