Medical negligence

My wife died on 11 December 2018 due to cancer.there was tumor in breast from long time.suddenly it become growing very fast.local dr advised for biopsy.biopsy report confirm its cancer.i rush for cancer hospital after so many test he said for biopsy.biopsy test confirm its benign tumor not cancer.he said for re biopsy.2nd report confirm that its benign.dr decided for simple mastectomy.after whole breast removal again biopsy was done.third report also confirm that it is benign tumor.after that dr discharged from hospital without any chemotherapy or radiation.after six months pain started in backside of left arm.local dr advised for MRI test.this report confirm that it is metastatic.i again visited previous hospital.there dr advised for biopsy and report confirm that it is TB and started TB medicine.after confused I visited another hospital he advised for biopsy and CT scan and both report confirm that it is metastatic.when I show all the test report to dr he said for re CT scan.this report confirm that it is metastatic which is post operative carcinoma.after report dr advised that only radiation is possible for you.i ran for radiation.their dr advised radiation is not possible.you go to tumor board.tumor board decided for three chemo.now chemo dr said I will review out side biopsy.i arranged the slide and after review he said that cancer spread all the body.i was new I asked him which stage is this he said nothing is beyond in this case.it is better to serve him and written painkiller.i was shocked and alone I came back home.but after few days she was paralyzed and pain was too much.i again visited hospital to relax atleast pain.iwas advised to go tumor board.the border written 3 test pet scan biopsy and harmonal test .I was trying for all test but in the meantime she passed away.my son in class 9 is under depression.myself in depression.lost private job as from September I am on leave.i want justice only.sir suggest me what to do