When you share your entities to a third party you grant permission to your particular item - project, dashboard or folder.
But the collaborator you're sharing to needs related system role to access the enable functionality for his profile.
Probably your collaborator lacks one of the following roles:
- Dashboard Manager - user can create dashboards and edit the ones have been shared to him
- Database Manager - the same for raw data sets.
Contact your Supervisor to configure roles to your collaborators.