Why not leave them in until he's 12 months? Change them as needed, but put them back immediately. Is he done teething? They're supposed to come up and down for teething. I also notice he's a coat. Have you tried shaving the problem ear and removing all the extra fluff? I came across someone who had the same problem with their longcoat but as soon as the person shaved the fluff off the ears, boing they went, they stayed up, and I believe they're fine now. Just had to get the weight off them in order to allow them to set in an erect position.