We won't ever get as much money from his sale as right now.. 120m means Nainggolan(50), Manolas(40) and Keita (30) at the very least and those players would improve our overal squad.
I like Dybala and wish for him to stay as he's world class but if he goes we can replace him and improve our squad overall.
Buffon
De Scigilio - Manolas - Chiellini - Alex Sandro
Pjanic - Marchisio - Nainggolan
Douglas Costa - Higuain - Bernardeschi
And then you have Mandzukic, Cuadrado, Khedira, Keita on the bench or for rotation.