The nervous feelings WILL transfer to the dog, I know- I am in the same place and working on it, though it's a different fear, I dont fear him biting anyone. Has he EVER tried to bite anyone? What was the dane's behavior through all this? Danes are HUGE (I used to own two) and they CAN and DO scare other dogs just because they loom over them, not to mention a 6mo dog who started out timid and is now entering and smack in the middle of their fear stage! You have to protect him. I second the training. Search here for confidence building. Work through obedience! Have the kids work on obedience with him. Engage his mind. Set things up for him to WIN. I also say no more parks, and play dates with his friend ONLY.
Absolutely no more talk of putting him down IMO. Preemptive.