So sorry  for your loss. I feel the same lost my Penny ️ on the 6th November 2019 From Mets Breast Cancer lasted just 3 weeks after diagnosis was being treated for Sciatica by GP after  complaining of back pain it had spread to her spine.  This after I had been diagnosed with Prostate cancer just after last Christmas had Radiotherapy in June/July 2019 again GP said I had piles after arguments with GP finally got a PSA test when they told me I didn't need one came back sorry you've got Prostate cancer. Don't care much anymore Just miss my Penny ️ so much cannot understand that Penny ️ was at stage 4. On research Penny ️ could have had it in her body for a least 2to5 years. 2 of her brother's had been diagnosed with Prostate cancer before myself. At the time only after researching did I come across that if a family member like brother has been diagnosed prostate cancer the sister has a chance of Breast Cancer due to the Gene being closely linked .  Please try to be strong I know it isn't easy I feel for both your son and yourself.