Does Radiation Treatment Targeting Only Deltoid Plemorphic Sarcoma At The Upper Arm Compromise The Lower Arm?

My husband was diagnosed with a Popeye muscle on his bicep in Nov 2016. He s was told to use ice and heat on it until Dec. when a dermatologist suggested seeing a specialist. Saw the orthopedic PA who took X-rays and said ice and heat. Two days later the surgeon saw us because of the extreme pain, ordered blood work, a CAT scan, and an MRI. Technique: multi planar multi sequence MRI of the right shoulder without intravenous contrast on Jan. 24, 2017. Indication: right/deltoid plemorphic Sarcoma. The ortho doc never mentioned sarcoma and had he done the MrRI further down the arm they would have realized there were tumors below the elbow. The surgeon did surgery on Feb. 3, 2017. He said he d removed the mass/tumor that presented as the Popeye muscle, and sent it into pathology, calling 3 days later with the news. We were referred to the Sarcoma clinic at the Lemon Holton Cancer Center in Grand Rapids MI. After the plan was presented, radiation then surgery. The only problem is, they did 5 treatments on the upper arm, and only when I told the Radiation Oncologist he was to have radiation below the elbow too, the last two treatments have included all infected areas. My question is, has this compromised his lower arm? The sarcoma Oncologist said the arm was already contaminated by doing the first surgery. My husband is 70 years old, extremely active, golf, water aerobics, wood workers, etc. we don t want his arm useless.