Jimmy suffered a rodeo crash and burn at the end of season 3. Kasey was in a fire fight in him office, Beth took a bomb blast and John got ambushed and shot. Rip is going to find John because he saw the buzzards circling near by, so he will be saved. I think Jimmy is gone.
I dont know how you know hes not but rumor is "someone" gets killed off the show. It aint Jamie either, hes behind Johns ambush shooting with his biological dad.
It has to be Jimmy as hes not part of the family and had run his course on story involvement.
Thats just my opinion of course