@melissasparrots they are all of the above
Well, if they are flopping around trying to get away when you approach, then you do have to worry about the chick picking up on that. Since he's a single baby, I'd still be inclined to let the parents raise him. If it were me, I'd probably focus on trying to get as much socialization in as possible before he fledges. If the parents are willing to accept him back in the nest after a couple of 5 minute snuggle sessions a day, try extending it to a couple of 10 and then 15 minute snuggles. Once he fledges, he will be more prone to pick up on his parent's anxiety. However, cockatiels are really quite good at maintaining tameness compared to other species. The problem with trying to hand feed a single chick is that you'll be checking temperature a lot more often because he won't have a cuddle buddy and generally its better for them if they have another bird to snuggle up with. That goes double if you haven't already hand-fed a whole bunch of babies before. If you aren't super experienced, I'd leave him with his parents. I just see a lot of stunted and sad looking baby cockatiels around with poor feather quality because someone thought they needed to hand-raise and didn't know how to do it to maximize growth. There is more to it than just reading some books and following an internet expert's advice. When you boil it down to the bare minimum of what is in the best interest of the chick, if you can maintain even a shred of tameness, I'd leave him parent raised. Once he's weaned, you can work with him even more. For that matter, once he fledges, if you've already worked with him on step up and perching on a hand, it may be as simple as reaching in, having him step up and then you can take him away from the cage for a few minutes of fly around and socialization time.