Any ideas what this is?

[Laura's Babies]

My daughter Rie just told me her dog "Sparky" Is having a problem. She said it seems his right side just gives out and he falls down. He is old, is graying around his nose but until this started has been lively, active and never had a history of anything but good health. She has an appointment with the vet tomorrow for him. In the meantime, I am worried about my Grand-Dog and was wondering what this could possibly be? A stroke? Or what?

Sparky has been such a wonderful dog. Showed up on their back door step, many years ago, refusing to leave and following my Grandson Cory everywhere. He is such a valued member of the family and a dog anybody would be proud to call theirs. He is part border collie and just a beautiful, the sweet boy.

[Daisy and Delilah]

Laura, I just put up a thread last night about the same thing happening with Delilah. It might help you get some ideas.

Thoughts and prayers going out!!