To be honest, my brother's cat a few months ago had been loosing weight quickly in the space of a month or two. I assumed it was going to be all down hill for him at the time. He did not eat as much and reminded me of the old family cat. Since then the cat has been given pills and the vet told my brother to feed him whenever he comes asking.
Since then he was had lots of food and it is only recently this mice business has started. I think he used to do this when he was young. He is an old fella now, but it still seems he can cut it when it comes to catching rodents. I am baby-sitting on Friday night at my brother's house, I hope he refrains from such activities whilst I'm there. I've never picked up a dead mouse/mole before.
I should add that he is getting better now and is gaining weight. Looks like he will become the fat cat he once was.