Hello~During the surgery, he could have had his neck in a bad position and this could be causing an impingement of the nerves, thus, causing the tingling. I would first, tell the physician what is going on, then, I would see a chiropractor, if his neck has some vertebra that are out of alignment due to how it was positioned, the chiropractor can fix it and his numbness should go away.
is it possible the neck biopsy surgery caused a litlle bruising near a nerve that feeds to the fingers? if so maybe it just needs some cold packs and time for inflammation to go down but let his doctor know, especially as he has a heart condition. some heart meds can cause coldness in extremities, not sure if that is the same as the numbness he feels though.
if it is when he sleeps he could be sleeping on it wrong or he could have low blood circulation in his hands....if not then ask your medical docotor what the side effects for the surgery...brittany
could be a post surgery effect, could also be minor nerve damage from the biopsy.