Loss of chinchilla

On may 10,2021 I lost my first chinchilla. This chinchilla was very special to me because his first owner was my sister, who has passed. He was the only pet she had at the time. He lived for 9 years. His death was sudden which is why it’s much more difficult for me to process.
I feel terrible because I wish he would have lived a longer life.
He’s left behind his cage mate and it worries me.