Yes, you can do this as long as he doesn't interact with anyone - every player has 1 character at a time, so you can't play as 2 characters (your Senator and his son for instance). Your character may talk to him but he can only sit there. This will change at some point in the future probably, but for now I want to see how the Faction Meetings are going to work out.
What i intended was a "Hello rest of the blues, this is my youngest, and my chosen sucessor in the senate, now get in the corner and take notes" i think that fits into your limitations.