I slipped a suggestion to my sister-in-law the other week, noting that it was just a suggestion that she may not have realised could be pretty effective and help her out. A lot.
I could "board" their cat while they were away for a little while, other wise it would be a hard decision about what to do about the 16 year old male cat- Oscar. Poor bugger had been upended from Sydney to the country, then back to suburbia, then left "alone" some time of the year while they were OS-where her dad looked after him. I think our 11 year female cat Fluffa should survive him. The gels loved the idea! So here is the temporarily live-in-cat: