Mine were seed at 4 weeks. I would give a syringe 1x a day but they really didn't want it. Just make sure you see him taking water too. If you notice any weight loss you can help out. I let mine go the way of "I see you can eat, I see you eating, when your hungry , you will eat". I'll assume there's an adjustment period for the baby.
. Seems every day his tail grows longer! He is 5 weeks but was spending all day just sitting in the nest cuddled next to mum so I've done some renovations and have hung the cat carrier from the roof of their cage so he can run round under it as well. Now he jumps down in the morning and has to spend the day exploring till I put him back up there at bedtime. I am still very rarely seeing him get a feed from dad but mostly the parents are encouraging him to just eat the food. They both still give him little preens around his face though which is cute 
