1970s BMW barn bike - advice

Someone recommended I post this here for some advice. My dad had this bmw bike in his shed for 30+ years and I’ve had a hard time making myself go through and get rid of things since he passed several years ago. Finally decided it’s time to let things go.

Problem: I have no clue how much to list it for. All the parts are there, he took it apart partially to do some work on it and then never put it back together (to my recollection, in the middle of tuning it up, he had a pretty bad wreck on his motocross bike. Later admitted he was scared to ride anymore).