I never needed this but I have heard success with using foam hair curlers. Remove the plastic part and use the round foam in the ear. Just don't let it slide deep into the ear. Tape it in with paper tape (you can find this at most drug stores like CVS or Walgreens) around the ear. Paper tape won't pull out the hair when you remove it. It's much gentler than gluing.
I also suggest encouraging chewing. I have heard chewing strengthens the jaw muscles and that helps the ears to stay up. Bully sticks, marrow bones, nylabones, antlers.