I had to put my 14 year old dog down last year. It was horrible of course, but like your mums dog his meds couldn't be upped any more & had stopped working. On the day we took him to his favourite walking track/park, spent some time with him & had those last pats/cuddles. This helped bc I had nice memories of the day, rather than just sitting around waiting for the time when we had to go to the vet. The vet was very good, explained what would happen step by step, we stayed with him until the end & were given as much time as we wanted when he was gone. Maybe you could chat with the vet & find out their process so your mum knows what will happen, might help her on the day. We ended up getting him cremated, and we still chat to him (ie 'don't destroy the place while we're gone', sometimes I will put him on the couch as a joke bc he loved being on there... might sound a bit odd/morbid but I find it's easier to keep a lighthearted attitude). He was like a child to me, I had him for 14 years & we'd been through a lot, so I totally get what your mum must be feeling. I'm not sure you can really 'do' much else for her, other than be there on the day (if she wants), make sure she gets a couple of last photos with her pet. It will be a rough day. Going home was hard, with no pet there anymore, so maybe hang around for a bit with her afterwards too? And bring tissues. Xx
Thanks Andie78, I love the idea of taking him somewhere he loves.. I think mum and dad will be doing that Friday arfternoon, taking him for a drive, he loves the car. And I think she is getting him cremated also, as she had the same done with her bulldog who died of a snakebite a few years back. She's known for a while that it will come to this, and she even got him a little friend to play with about a month ago until the time (and to help her after I suppose) in the form of a little Silkie girl.

When we had our JR put down, it was sudden but I know it was the best thing for her. The told us if she was a person she would have been in an old persons home and carefully monitored as her mind was going.
It was hard but the vet was wonderful. We paid the bill while he was doing it then waited outside until he brought her out to us. He did all this with dignity which made it easier. Even the wrapping she was in was lovely.
She is now buried in our backyard and the grandchildren know where and were able to talk about it. They will still refer to her even though it was over 12 months ago which is lovely as they have such lovely memories of her.
Make sure they have a lovely picture of their dog so they have something to look back at.
All the best for Saturday as it is going to be a hard day.

Thank you Rivlas, mums a photographer so she has so many photos of him, he's always been her little model we actually took some of him last night, and I'm sure there will be loads more in the coming days.

Thank you both for your lovely replies and stories of your own experiences. I personally have never dealt with a pet loss like this before, I've either been too young or not around at the time. It will be hard on everyone who knew him, he is such a sweet thing.