He's staying with my DPs for four days, he'll be fine, they love him & will look after him and spoil him rotten (once we start heading to their house on a walk his tail starts wagging 
)
But . . . he's 15, going on 16, this sounds awful but one day he's just not going to wake up :( I'm getting more and more twitchy that it'll be while we're away and my elderly dps will have to cope.
We have talked about it, and they've been there themselves more than once as they're doggy people, on recent visit vet said DDog was in decent shape for his age & his heart is ok, but . . . but . . .
(We're going as rest of DH's family live 5 hours away and his sister/her DP work shifts & only get Xmas day off, I've not been the last 2 times they visit, & DH reasonably wants to spend Xmas with his folks, first time for several years.)