Brain tumor. Neurosurgeon doctor!

My dad`s brain tumor surgery done in 2010 & again in nov 2015. now recent MRI shown again tumor. It`s cancer type tumor but now what we can do. as already two operation done. I consult with our previous neurosurgeon Doctor regarding this they told that third operation is not possible in this stage. They advice us for Radiation treatment. Also they told us that Radiation is not as useful in this case. So I consult with Radiologist for the same, they told me, we can do this but we are not assure that after this treatment Tumor will not growth. As one 7cm tumor is in left lateral ventricle with mid line shift of 6mm towards right side & other 3cm tumor in his small brain also. We can not remove tumor by Radiation. We can just kill those cells which is attached outside the tumor. So Please suggest me for this case.