Giving a Collaborator Access to One Site and MYSQL server Using His SSH Public Keys

I look up “SSH keys access to UserMIn” but found no results

I don’t want to use Passwords.
Is it possible to give a user access to

  1. one server in Virtual Min (SFTP)
  2. plus access to MySQl server

so that
a) he has privileges to create a MYSQL data base, and manage it
b) SFTP access the server.

Using his SSH public key, which I would be able to revoke if needed?

USE CASE: you have a Software developer in India. You would like to limit his “scope” and be able to revoke him any time. Passwords are vulnerable.