If you can borrow traps I would have them fixed then drop them back to your parents. It would be a shame if they had a litter or two!

I believe someone dropped three adult cats off in my village (they just appeared one day). One of them adopted me and after a couple of months I managed to get him to the vets for the big snip, one disappeared, and I think one is living in the church square. People who dump animals are just so mean!