I opened up an exterior wall and found a lot of termite damage. They did a number on two load-bearing studs and the sill plate they're resting on. To get a sense of the damage, I cleared out as much of the former nest as possible. It looks bad to me, but I'm not sure how bad. Obviously the house isn't collapsing, but I'm doing work within that wall and don't want to take any risks. Would sistering a new stud be sufficient? Could I plug the big hole in that sill with concrete?
Here are the pictures: