What exactly do you mean by "pending"? Do you mean approved but pending?Like, he received the approval letter, but not the card itself? Or, his application hasn't been approved yet?
The problem is that when you greencard is "pending", it can last anywhere between a few weeks and a few months, or even years. I was an International student and applied for permanent residency about 3 years ago. My greencard got "approved" this year, in the Fall. Then, my status was "pending" for about 2 months, and I just got my card a couple of weeks ago. My brother applied at the same time I did, was "approved" before me (in the Spring of last year) and is still "pending"... meaning that he still does not have his greencard in hand. it's been almost a year for him!
It can be random and depends on a lot of things like gender (not kidding, if you are originally from the middle-east, like I am, you are much more likely to get your greencard approved if you are a female), country of origin, date when you applied (before or after sept 11, war, etc) and your original status (it's harder to try to change a student visa into a greencard, for example).
But, if he is in the process of getting his greencard and leaves the US, it'll be over for him. He won;t be able to come back here if he leaves the US now. He has to stay and get the greencard first. But, Ross is very understanding about that and will let him defer for a year. I applied there last year after not getting into US schools, was accepted, then ask for deferment because of the visa issue, and got the deferment.
I ended up using the year off to re-apply to US schools and will likely get in somehwere in the US this year (crossing fingers!
)... But the point is: he has to ask for a derferment.
Hope this helps a little. Gluck, I know it sucks.