I have to agree with Jay about leaving the other baby with yours for the time being, you are the one doing the feeding and should continue to do so until they are both weaned then she can take hers home, she will still bond with her bird even though she didn't handfeed it. Don't let her talk you out of it either, you know what I am saying Tanya, stand your ground and tell her we said so, in fact tell her to come here and join and we will tell her ourselves.
I personally think your cage will prove to be too small for a grey unless you plan on having him out most of the day for when you had some toys inside there wasn't much room left for Jackson but that is my opinion.