The first thing we would advise is to make absolutely sure the bird is weaned. Does he eat the seed or pellets you offer, have you seen him drinking water, and have you offered him fresh vegetables or treats and seen him eat those? If he isn't eating these and isn't being handfed, you've got a bird that could be starving.

If the bird is eating and drinking well, that's great and you're problem may not really be a problem, just a very young cockatiel. You don't mention how long you have had your bird and that could be a key in knowing if he is adjusting to a new home. Two months is very young and some cockatiels appear to be more shy than others.

Check to see that he's eating enough, and if he appears healthy otherwise, give him a little more time.