I'm no doctor either!
My fear is that he's not all that healthy. He is clearly obese. He is being treated for high cholesterol and (maybe?) high blood pressure. There is every indication he has some level of atherosclerosis. There was the surprise visit to Walter Reed a few (?) months ago. There is his constant projection about how "weak" Biden is (probably the best indicator). There is having trouble walking down ramps and drinking from a glass. The latter may be aberrations, but who knows? They have certainly not been fully forthcoming about his medical history and health status.
Remember Boris Johnson's case? He was fine and working from home for about a week, then suddenly had to go into the hospital and was in the ICU for 3 days, and nearly died by his own admission. Johnson is about 20 years younger than Trump, and not as obese. Maybe he has some other comorbidity, or just had bad luck. Ultimately, he was largely out of commission for almost a month. That could be among Trump's better scenarios right now.
I think obesity is a significant and underappreciated comorbidity. If you notice all the cases of younger people (under 65) who died and are reported as having no contributing factors, most appear to be overweight. (Anecdotal, I know.) It may be second only to hypertension as a risk factor. Here's a paper I haven't read, but might be worthwhile:
Obesity, the most common comorbidity in SARS-CoV-2: is leptin the link? | International Journal of Obesity