I have a business associate who is trying to continue to work but health is wiped after recovering at home from covid.. 60'ish.

Very low energy, shortness of breath. What they call the 'long haulers'.

I have thought of remedies to boost his immunity but not sure what to offer for the other lasting daily symptoms.

Wth does this shit do to the body and what systems. I know lungs and can make medicine for that but what about weakness? What body system would that be?

Anyone have experience with this? Thanks in advance.