If he is open to alternative therapies, I highly suggest organic apricot seeds (Vitamin B17/Laetril).

My mother-in-law had bladder cancer that kept coming back every year during her yearly check and had to be operated on repeatedly every year.

I gave her a bag of apricot seeds and she took 7 seeds per day. She has been cancer free for the past 4 years now and the doctor told her he doesn't know how she is doing it to keep this aggressive cancer at bay but to keep doing what she is doing.

My wife and I take a few of these every day as well to keep cancer away. You can look up organic apricot seeds on Amazon.

More on them here:
https://thetruthaboutcancer.com/apricot-kernels-for-cancer/

The main stream bad mouths them because they actually are effective without using damaging main stream cancer treatments/big pharma.