<human>: Hi r/cats!

I am coming to you today on behalf of my mother; one of her cats passed two weeks ago at the age of 11 and her other cat - a 12-year-old boy who has never been an only child - is incredibly lonely. He cries at night and wanders the house looking for his sister, and when my mom goes to work every day she feels terrible leaving him alone without a snuggle buddy.

She wants to get him a companion but isn't sure if she should be looking into a kitten or an adolescent or a grown-up cat or what. I figured I would pose the question to the experts and see what you come up with.

Thanks!

Can you condense the text into three sentences or less?
<bot>: one cat died, other cat (male, 12, never been alone) is very lonely. What should we do?