I am sorry Henry is sick. Poor baby.
My neighbor's dog, mini Schnauzer, came down with the same thing
two months ago. It took awhile on meds but she is now fine.
Buddy and I are wishing Henry a speedy recovery.
Just keep him warm and comfortable. If he goes outside to potty
make sure he has a sweater on unless it's warm where you live.
Didn't look at your location.
Of course give him his meds too
