Well, you could, but probably not through an Esri API. The "USE database" is incompatible with the Enterprise geodatabase connection file (.sde) being linked to a specific database.
In theory, the USE isn't required, so an arcpy.ArcSDESQLExecute() request could issue the GRANT command, but the principal benefit of using an Enterprise geodatabase is to take advantage of versioning and geodatabase behaviors, and only a tool like ChangePrivileges is going to know which tables participate in geodatabase functionality, so if you roll your own, you might have permission issues later on down the road (for example, feature datasets have the permission of the least access of the members, so if you miss one GRANT, you might not have any access at all).
- V