Each type of brain tumor can have a very different familial association. In general, tumors at a younger age are more likely to be inherited than those at an older age, which are more often spontaneous. For all primary brain tumors, it looks like about 5% are known to be hereditary. The precise risk is difficult to calculate, but since he got the tumor at an older age, and assuming no one else in the family has had other unusual or early cancers, I'd think your dad's cancer was most likely not inherited.
