hi
well, with all sicknesses it takes time to recover so no wonder he's not 'back on track' yet.
if he's happy with 3,5 routine in terms of naps/sleep- let him do that.
but if he's not hungry at 3,5hrs mark, you need to wait a bit after he wakes up and don't feed him straight away but maybe after 30min or so upon waking.
so you'll have AEASAEAS kind of routine.
does it make sense?
Monika