Before you consider talking your friend into giving you their bird - first consider whether you are capable of caring for a macaw.
They're incredibly different from a budgie and from what I've scanned in your post, PJ is your first bird?
You also want to think about whether you want your birds to be out together. It is uncommon for birds to get along without having met first, and it could mean that your relationship with PJ could change before you've really got to know each other.
Is there a bird rescue near you that you could inform about this? If you are sure your friend is neglecting their bird and you think their wellbeing is in danger, you could also contact the local animal organisation (in the US that's the SPCA, right?) for advice about what you can do.
Once the macaw is in a situation where their needs are being met, you could always volunteer to foster the macaw if you're interested in owning him/her eventually, or you could just volunteer at the place to see how he/she is going.
I don't know how your friend/s would feel about this but (at the risk of being a bit incendiary) I don't know how I'd feel about a friend of mine if they treated an animal so poorly...
That aside, have you spoken to your friend about their bird to find out what's going on? Are they sick and can't care for their bird, did their macaw somehow frighten them (like with a bite) and they're now scared to go near them? Or are they just not interested in providing the care and want merely to look at them? Sometimes there are innocent reasons a bird isn't getting the care they need that can be resolved with a bit of guidance, and many owners are just not educated enough to care for parrots. Other times...
It sounds like the Macaw's having a hard time - if he's pulling out his feathers it could be for a multitude of reasons and it's sometimes hard to come back from it. I'd do something sooner rather than later if you want to help.
Oh, and thanks for coming to us. I hope the macaw catches a break. Sounds like a heartbreaking situation IMO.