As some neighbors of mine have had Dobies for years, once the ears don't stand up, they never will. Taping them won't do any good if it's been a while since they were cropped. Sorry, but I think it's kind of cruel to do that. Let them be.
I adopted a year and a half old doberman, her ears were cropped but don't stand. They fold over. Would it be a waste of time to tape the ears?
I adopted a year old dobi at one time, her ears had been "cropped" whoever did it, botched her ears....when she was excited, she could hold them up, otherwise they pretty much stayed out to the side like yoda.
I agree that cropping ears is cruel, as to do it properly, not only do the ears need bandaged, they need stretched every day. Natural ears on a dobi are the way to go....it's in the dogs best interest to just leave well enough alone.
At this point, there is no point in taping them up. The crop was done incorrectly, or the blood vessels have been damaged.