heck yes get a second opinion. and a third, forth if need be. I don't know about it being risky, one thing for sure, it has to come out.

My sil just had a double mas. , chemo and radiation due to doctor saying he could find nothing in her breast. The second doctor pick it up. Doctor says everything looks good now, tough woman

My sister just had 2.5 feet of her colon removed with a grapefruit sized tumor, second opinion from a doctor pick it up. Chemo and radiation, good to go now

Best of luck for your buddy, be there for him when he needs you.