Thanks for writing. Two or more people can use the same Pacer. The key is that you will need to "Change User" within the miCoach Manager in order to ensure that you and your dad are not mixing up personal settings and training plans.
Here is a guide that gives you the complete list of steps and answers your question in full:
The number of cubes within your status image is determined by your activity on the miCoach support website. These activities include (in order of importance):
Having a response to a discussion post marked as the correct solution.
Responses which are marked as helpful by other users.
