Yes. If you have proxy access to another person's MyChart account, you might be able to give an app access to their health information. During the sharing process, you select whose information to share. The app can access information for only the person you select.
Give an app access to your health information or a family member's information.
Go to the Sharing Hub in MyChart to invite someone to access your record or to request access to a family member's account. Each organization has their own rules around proxy access.