In medical-speak, any word with -ectomy on the end usually means "surgical removal of."
So a "colectomy" would be surgical removal of the colon.
"Hemicolectomy" would be surgical removal of half (hemi, like hemisphere) of the colon.
If you look at anatomy, the colon comes from the small intestine on the right side, goes up, then across the belly right to left, then down the left side. The right side that goes up is the ascending colon. The part that goes right to left is the tranverse colon. The part that goes down the left side is the descending colon. Then it meets the sigmoid colon, then the rectum, then the anus, and out.
Friability is another medical term used often in endoscopy when the tissue is brittle, or it breaks apart easily when touched. Healthy colon tissue, like skin, should stay intact when poked, but friable colon tissue will break apart when poked. Think of wet tissue paper, or, conversely, really dry, arid soil that's all cracked.
Friability usually responds to prednisone, and it also often responds very well to Remicade/Humira/etc. Friability could be a reason why the surgeon would be hesitant to try a resection (because it is possible it would be too weak to hold the resection), but again, this is where meds could help before the surgery is undertaken.
Patients can and often are put on Remicade or Humira *before* having surgery, and it's generally considered safe to be on one of them while having surgery. It's possible that one of those meds could heal up the remainder of his colon so that it could take a resection successfully.
As for resections, they can be either in the colon or the small intestine. Probably the end of the small intestine is the most common site, but the colon is common as well.
And, yes, the stricture of scar tissue usually comes from active disease scarring areas over time. In some people that process takes decades. In others it takes just months.
It sounds like you and your husband are learning quickly how to deal with this and I commend you both for that. Good luck with the second opinion.