While I try not to be too specific when I write about other people here (not my story -- although this is, partly, because dh & I have been affected a lot too), it's becoming harder to write honestly about what's been going on without adding at least a few more details:
The "major surgical procedure" I mentioned? It's an organ transplant -- one of the few that can be done using organs, or parts of organs, from a living donor. It is BIL's only real shot at regaining some quality of life. (And, while they're at it, they're also going to repair the hernia that has been bothering him for quite a while now.)
After assessing a few of the potential donors from within the extended family, who very generously volunteered to be tested for suitability (just one potential donor gets evaluated at a time, to conserve scarce medical resources), the transplant team decided that Older Nephew (Little Great-Nephew's dad) would be an excellent match for his dad.