Does he have client side encryption enabled from the Android apps settings?
Hello Guys, i have the same problem with the iOS App:
- i create 2 users: user1 and user2
- user1 create a library with passwort-encryption
- user1 share this library to user2
- if user2 wants to open the encrypted library from user1 in the iOS App, he dont get a prompt to enter the encryption-password and can access the folders
- user2 can access to the folders in the encrypted library but a download-attempt failed (because of the missing encryption-password)
Can someone test this constellation again and give me feedback or how i can solve this problem? 
System-Info:
Seafile 6.3.2 runs on raspberry
iOS App 2.7.8
This is app bug (@xiez ), but for clear this. Seafile not encrypt whole library but only file content like other encryption system do. So read file list in directories is OK (if library is shared to you), read content without password should not be possible.