Hello Debbie and welcome to the family, so glad you could join us and we look forward to hearing more about you and Greyson.
I'm so pleased you could find it in your heart to take in an abused grey, not everyone could handle that but with a lot of time and much patience he should turn out to be quite a good companion.
I would imagine he is still a little scared and with much time spent with him he will eventually trust you enough to let his guard down and bond with you. How anyone could abuse one of these awesome creatures is beyond me but he has found a forever home now and that is all that counts.
I would try to include him in as much of the goings on at your home as possible, sit beside his cage and talk or read to him, show him how to play with toys and encourage him to want to be with you. He probably feels safer staying to himself but he won't be able to keep from wanting to get into the middle of things if you make it so appealing to him he can't resist.
Thats great he has a teacher in your green wing, she can help him know what is expected of him and is some company to him, maybe the two of them will become friends in time.
Please read thru the many threads for lots of useful information and do ask any and all questions you may have and we will help you in any way we can.
If you have any pictures of Greyson you would like to share with us we would love to see him and you can post some of Myah in the other birds room if you like. :)