They shouldn't pick on each other, unless she has predatory fish and the other tankmates are small. What kind of fish does she have?
She can have someone come in once a week. Aside from feeding, perform a water change, but after awhile of the feeding.
Don't allow the person access to the full container, they may feed too much. It's best to use one of those
1-Day 4 Compartment Pill Reminder and place enough fish food in each container for each feeding. This way, they won't be able to overfeed if given the whole fish food container.
If she has a timer for the lights, set the timer to only go on about 4 hours a day, so the fish sleep or rest most of the day.