NEED ADVICEve

Hi. my name is Charlotte. I really don't want to ask this. I have had a small poodle for 16 years. I got him when he was 5 weeks old. He has been my constant companion and has gotten me through many dark painful nights, including a long bout with shingles and the sudden dearh of my husband in the miiddle of the night. He is the sweetest, most humble little creature I've ever seen. My problem? He is both deaf and blind. However, Vet says that his heart is excellent and he seems to be healthy. He can find me anywhere in the house and he starts barking when he hears my car pull up. Strange that he hears that but nothing elsee. He wakes np in the middle of the night for water or to go outside. Now. I have had several people tell me that I should let him go, put him down. They say I am being selfish by forcing him to live in a dark lonely world. Am I? Is he miserable? He doesn't seem to be but how do I know?
Please I need advice from some one was exoerienced this.