My best friend has a 10 year old Golden Retriever....and was advised by her Vet to get him fixed, because...?

despite his being a ' purebred stud' the Vet said that the dog could get testicular cancer, and fixing him at 10 years old would keep him healthy. The dog is not doing well at all, and my friend is very upset and feels guilty. What is the life expectancy of a dog (over 100 pounds) and would other Vets recommend a neuter at such an advanced age? I think to suggest this at his age was cruel. Any comments?