It depends on the level of brumation your dragon goes to. Some just get lazier during the winter, some sleep on and off every couple of days, and still others go to sleep and don't wake up for months. If your dragon is awake at all, you want to continue with regular feeding,
bathing and lighting schedules. If your dragon is sound asleep, not waking up at all, then there's no need to run the lights or offer food, just let him sleep. It's always a good idea to peek in and make sure that he looks okay - some dragons can become slightly dehydrated and if that's a worry you could wake your dragon up every couple of weeks for a
bath and make sure he's dry again before letting him curl back up and go back to sleep.