poor windie cat

my elderly cat (18+ years) is not doing so well today. My mom found him this morning with his leg caught and it seems that both rear legs have lost all power.
He’s at the vet and is going to stay there over the weekend to see if there is any improvement. If there isn’t we may have to put him down. It’s so difficult. He is old but he is fully aware. Watching him this morning trying to maneuver without use of his rear legs was just heartbreaking.
anyway. that’s going on.