Min,
Supplemental feeding is only necessary if the hive is weak. That means there are not enough bees to make enough honey to get them through the winter.
In the case of a weak hive, placing a feeder tray on the top of the hive but under the cover, and filling the tray with a sugar syrup of 2 lbs. white sugar to 1 lb. water will feed the bees for a while. The tray needs to be checked about every two weeks and refilled. Do not use corn syrup--it is suspected that corn syrup feeding may contribute to hive collapse.
If your friend is talking about bees that are not in a beekeeper's hive, then supplemental feeding will only attract rodents, wasps and other undesirables, since the food will be out in the open. Is your friend even sure they are honey bees?

marlingardener thank you for your answer. yes, these are italian honeybees or a kind very like them.
the hive seems to be doing very well, maybe too well because it is huge and who knows how long the shrub can hold it up?
min