Marty, considering his age i would say the head movements would be a feed resopnse. All baby parrots of that age do the same thing. As weaning goes that will depend on your bird but usually he/she would be about 10 to 12 weeks before being independent. But don't rush him let him wean at his own pace. You just offer all the soft weaning foods. he will require.
Offer food at different parts of the cage or place where it is easy for the bird to see and get to. Millet spray, apples, corn, greens as in peas, beans & leafy green veg. For a while the chick may pull and nibble and not eat much at all, then all of a sudden it happens. The chicks will still beg for you to feed, keep in mind you should be still feeding them 3 times a day at this point. Once you see they are getting the idea and food is being eaten, you can lower the feeds to 2 times daily until they have got the idea to do it on their own. Weaning parrots can take from 2 weeks to 2 months depending on size. I also soak and sprout seed for the young I found it helps them to get the idea on how to hull the seeds, as they are a lot softer to eat.