As far as Im aware he had no symptoms of Covid I may be wrong. As someone who has also had it, I had very mild symptoms (no smell) and Im a few years older than Andy and I dont feel any side effects so Im not sure that will a reason for him either.
I do appreciate though everyones experience is different, I just think its doubtful we will see him playing tournaments as often is required to get back into the top 50. I also hope he doesnt go down the doubles route, for Andy that would be pretty pointless. I can see him coaching in a couple of years think thats where he will be at going forward.