To me, fledgling means he's left the nest. When my baby budgies "fledge" they are learning to fly and the dad bird continues to feed them for a few weeks as they learn how to eat on their own. My babies returned to the box frequently for a couple weeks after fledging and hung out with Mom as she incubated the next clutch. Larger parrots are fed longer.
I would think this baby would still need parent feeding assuming he's parent fed from the wild. The problem with trying to begin hand feeding at this age is they aren't likely to accept it. Even my parent raised budgies won't accept starting hand feeding after three weeks old.
What I would do (after discussing with an avian vet) is offer lots of warm, soft food in a dish or from a spoon. Don't try to syringe feed unless you are an expert because it's too easy to choke him or for the baby to inhale it and die. Hopefully he's already eating well on his own.
Yeti is just adorable!
