Craig loved Stripes more than anyone or thing else. He loved Stripes more than his family or friends, when he was young. Though as Craig got older he found that he was falling more and more in love with one friend more than Stripes. That friend was Tweek Tweak, Craig found Tweek was becoming more and more to the Tucker boy than Stripes.
So when Stripes died Craig was heartbroken because Stripes died alone while Craig was at Tweek's. Stripes dieing made Craig realize how much he forgot the guinea pig to hang out Tweek. Though after Stripes death Craig almost never left Tweek's side scared that if he lost the blonde he would have no one.
He clung to the blonde all these years even when Tweek was buried at the age of 97. Craig was buried next to him at 98 of the same thing old age. Ironically enough what killed Craig and Tweek also Killed Stripes.