There are quite a few things that could cause problems like that. Some could be age and lack of strength, some could be balance problems. Not sure there is a good answer out there for you. I thought I would have my buddy until 13 or 14, he was lean and healthy and tall, but at 10.5 he got an aggressive sarcoma that took him in about 4 months. I have had a few dogs age and we keep them going as long as they are happy, even when walking gets tough. If they start going the bathroom in the house etc, it is usally time. I hope you have some time yet!
