55, so very sorry to hear this. Back in 07 I had to put my 9.5 year old dog down due to a brain tumor. His back legs went limp and he just howled in pain, went blind in one eye, loss his balance, the works. Vet said classic brain tumor symptoms. Horrible! But when he'd see us, he'd still try to get up and walk to us. Game as heck pitbull. He gave me more than I did him. You did the right thing, mercy. Unfotunately it's the worse part about having pets. I totally feel your pain.