Sick Guinea pig-the most humane thing to do

Question
Hi,
I have male guinea pig that is about 1.5 years old. In August 2012 he had an URI that lead to pneumonia. He recovered, but vet said he would never really recover. Since that, he had four URIs in six months. Now he has fifth. Everytime he's sick, he has diarrhea, lethargy, crusty eyes and nose and i just hate seeing him like that. It's just the matter of time when one of the URIs will be fatal. Is it fair to let him suffer? Or is it the right thing to do to fight it? I love him very much, and I want to do whats the best for him. I am struggling to make a decision. Do I have the right to take his life when he could possibly live a few more months? Or am I a monster to let him suffer when clearly he is never going to be healthy?

Answer
the animal community is divided on this, some feel that if an animal is alive, then it is trying to live and therefore wants to live and thus we should not put it down, the other side feel that if an animal is suffering then rather than leaving it to be in constant pain and stress for the rest of its life. i am personally for the latter, if i pigs immune system is shot then it will spend most of its remaining life trying to "get better" before it dies.

but this really depends on where your morality lies and which you think is the moral choice, you can only do what you think is best.