Restrictions:
Low sugar...you do not need to eliminate it, but many claim it feeds cancers, so restrict the intake.
Minimize processed / preserved meats.
Watch the carbs...OK to eat them, but not to excess.
I was told to avoid green tea and food / drink containing it when I was doing my induction therapy. Apparently it does not mix well with the Velcade.
I have been told no alcohol since the start of this MM journey.

Additions:
Eat fresh fruits and vegetables.
Foods rich in iron combat the low hemoglobulin brought on by MM (iron supplements with Hi-D vitamin are also helpful).
Foods rich in calcium were encouraged to combat the bone damage from MM.
Be sure your father is drinking plenty of fluids, it will keep the kidneys flushed. Vitamins C and K are also important to fortify the immune system.
I take a 1,000mg Tums per day for calcium to help fortify the bones.
Make sure to eat adequate protein.

A lot of literature encourages a Mediterranean diet.

Be aware the Velcade is likely to cause neuropathy, so alert your father's doctor at the first sign of it. Different patients experience in different parts of the body. For some it is in the feet, others experience it in their hands. For me, it was the little finger and ring finger of each hand.

You might find smaller meals, supplemented with snacks during the day (same calories as three large meals) is easier on the body and helps with fatigue.

Personally, after diagnosis, I have transitioned to eating a larger lunch than I used to and eating a smaller evening meal.

I eat whatever I want with no restrictions except no alcohol. I’m doing extraordinarily well.

This is our patient's bone marrow biopsy result, please if possible help to get more about the severness and degree of his MM

Check out Chris Wark on Square One he details all the anti cancer foods and gives recipes
https://www.chrisbeatcancer.com/carolyn-marin-o...

Carolyn Marin on Ann Wigmore's legacy and raw food for healing

https://www.chrisbeatcancer.com/carolyn-marin-on-ann-wigmores-legacy-and-raw-food-for-healing/

Just meat and vegs and fruits. Limit fats and carbs.