Dad diagnosed a 2 weeks ago with aml

My dad had no symptoms..routine check up found irregularities in his blood & a couple days later he is diagnosed with AML, stage M2 (I think)..he went in the hospital the following Monday (all w/in about 10 days of the diagnosis! and now he is on day 4 of the induction chemo.  He feels fairly normal, which is great but I wonder if anyone can tell me how long does it normally take for the chemo to really start interferring with your body's normal state & functions??  I just want to prep myself!  He is 68 yrs old and the Dr told us today he would def be in the hospital for at least another 4 weeks to continue treatment....this is so unexpected & so new to my family that I am at a complete loss & just cannot seem to focus on what the Dr is even saying some of the time due to my grief & concern...how bad can the chemo get or has any one actually ever witnessed or had an experience where the chemo did not actually get as bad as we are all petrified that it may get!?  or I just grasping here??  Any insight would be great...nervous wreak!!  He is being really positive, his faith and his spirits could not be any better...he truly is a Super hero & I cant even explain the courage & strength he in demonstarting---I believe this ALL has to have some contribution!!    Any stories or similarities?