Need an opinion for my father in law.

Hello Doctor, This query is regarding my father in law. last month he had a heartache. doctor did angioplasty and he was doing fine. Until few days back  he started talking absurd things and suddenly stopped talking. He often had  memory loss and felt dizzy. To our curiosity we went to a neurosurgeon​ where he was diagnosed with a brain tumor. doctors are suggesting for a surgery and possibly a radiotherapy. however a known neurosurgeon told- Despite sergery and radiotherapy there is a risk and he could survive 10-11 months. we respect what he said.. but want to take another opinion if sergery is required in his case or not 1.- if sergery happens and its not cancerous so what is his future? 2. if surgery doesnt happen what is his future? How 3. long can he survive? 3. if it happens and if its cancerous whats the future without  radiotherapy​. We are bit confused and doesnt want him to suffer.. we wanted to be sure if what ever happens, he should be able to live his life happily.