Physician's oversight regarding treatment and drug contraindication

I am a primary caregiver to my senior parent who is battling late stage cancer. I usually do a lot of research as due diligence to better understand treatments, side effects, etc. as I am also the one who coordinates with the doctors.

We just started a new treatment protocol because the previous one did not work. This targeted treatment is fairly new and is quite astronomical for our tax bracket, but we don't have much of an option at this point but to give it a try.

On the day of treatment, I had to persistently request for the nurse to double check with the fellow and the doctor multiple times that based on my research, drug A should be taken before drug B is infused. (This was after I waited and observed if this was the sequence ordered by the doctor.)

Another concern was regarding the take home meds. We were given the standard pre-printed meds, but again according to my reading, one of those meds should be stopped if taking drug A as it can reduce effectiveness and absorption of said drug by 50%.

It feels unsettling that these factors have been overlooked. We have a relatively good experience with our doctor but I believe serious concerns like such needs to be addressed because what if it happened to someone else who didn't know, or not have someone to advocate for them? I'm not certain how to go about it without sounding offensive and possibly straining the relationship with the doctor.

What would you do if you were in my shoe? Hoping for some patient's and doctor's perspectives.