I feel your pain.
Great dog that you have, I have no answers. We have a Schoodle most incredible dog we ever have. Schnauzer's are so intelligent as well as poodles.
Not sure if this made a difference but we always put Lactose Free Milk in his food bowl every morning after he ate his breakfast. Wow he loved it, he just stands there forever and wait for it to get poured in his bowl after he eats.
14 years old now, totally blind for the last two years, he still is an amazing dog, does everything a regular dog does, except he cant see, walks around the community and takes his cues from the leash on which way, its TRULY amazing how fluid he does it. The leash is like a joy stick a pilot uses on an airplane.
He barks at people when he picks up their scent. *LOL* Even from across the street.
Knows his way around the house and puts himself to bed. Still loves tug of war with a rope or empty water bottle.
Sad part is, we have to deal with the fact that he will not be with us next year. His doctor says he has about 6 months to 1 year of life left in him. Progressive heart Valve Disease. Right now he takes a miracle FDA approved heart drug two times a day and is 100% great but doctor says at some point dog the drug will not be effective. The drug is specifically for his condition and improves heart function to make up for the failing valves.
He is still 100% and we would never let him suffer, doctor is aware and assures us he is still 100% ok.
Sorry for going off subject except that I do wonder, if dog owners knew they could feed Lactose Free Milk if it would help in later years. I dont know the answer, except for all his other issues, he is amazingly good health bone wise.
Good luck, it's important to do what we can and make sure they are not suffering.
(he loves laying in my wife's arms at night while we watch TV for a little while. Mine not so much *L*)