pooping in house

Question
I have a 12 year old neutered male shepard that is kept inside at night. We live in North Idaho. Typically if he needed to make a bathroom run , he would wake us up and we would let him out. Recently he has not been able to hold it and has deposited on the carpet on the way to the patio door. Its as if he doesn't realize he has to poop till its too late. We feed him dry food twice a day, 8am and 4pm. A doggie door is not workable. If we feed him only in the morning would this pass through his system before night time? What can we do?

Thanks,

John

Answer
12 is getting up there for a Shepherd.  He could have some physical changes a vet could remedy.  Cutting out the second meal could eliminate the need for the middle of the night outing.  I woudl really like to see a vet visit before cutting out the meal.