Your friend's grey may have had some reason for the B12 shot so don't worry about that.
Do you provide any rough or cement perches near his food or water bowls? They tend to help keep the nails from being so sharp but if you think he needs it then by all means have them filed down some. An avian vet will usually use a dremel tool to do the job and it takes just a few minutes to do it.
The beak should not need a trim unless it is growing out of alignment, they usually do a pretty good job of keeping their beak in good condition themselves.
Some greys will be stressed out or upset about vet visits and will act accordingly but it varies from one to another, Josey usually takes her visits in stride.
Don't be upset or scared about taking him in to see the vet for procedures, sometimes it is necessary and that is all part of grey ownership, you take the bad along with the good but most of it is good thank heavens.