my dad had a surgery and everything went ok with him. He opened his eyes but he is not recognising anything and at the same time we did a scan for the brain and everything is normal? they said this is normal and he need more time and hi brain will wake up alone. He is still using the tube in mouth and the doctor told us that once he'll wake up it will be no more need for the tube and he can leave the ICU,

SO IS THIS NORMAL FOR AND OLD MAN TO TAKE THIS TIME TO START WAKING UP

any advice?