I adopted a 13 year old golden. Her owners died, the daughter took her pitbull brother but couldn't take both. The son wouldn't take her in. I had her for just over 2 years. I have never regretted it. She went camping, to the drive-in, and had a good few last years.
Several years ago, I adopted a 30+ year old parrot. He spent many years in a cage. He had bad arthritis in his feet, had mini seizures, and was overweight. Now, he is out of his cage most days, is active and has lost weight, his arthritis is almost non-existent. Very rarely has a seizure. And he goes camping and loves it!
Give the dogs new experiences and a happy old age. You will never regret it. Yes, they will be gone sooner than later, but they had quality for it. So worth it!