Young cancer pt was told to get hospice, mother decided to try radiation anyway, good idea or?

My BF son has terminal sarcoma, he had 3 blood transfusions last week, was told to contact hospice.Mother cannot accept this and decided to try radiation today.Will this just prolong his life, make him really sick, can it kill him immediately, I hate to ask her because she is at her wits end.All she can do is cry.Me along with her.She cannot face the fact of his demise.I am scared that this would put him into a coma, and being done for nothing.What would you do if this was your son?