Have you ever thought

1. Why he would tell you to help you on a senior position? Did you tell/hint him before about your ambition? Is he really kind of person who likes the other people grow faster than him?
2. What is the benefits he can get if you get the senior position? Then you can figure out why he wants to help you.
3. Is there a real position supposed to be created?

Be very careful, otherwise things may turn around to opposite direction.