Enquiry for Radiation after chemotherapy

My mother got diagnosed with CA breast in October last year. Breast Conservative Surgery along with sentinel lymph nodes removal on Right side done on 12th oct 2020. Chemotherapy started on 30th oct with Paclitaxel followed by Adriamycin and cyclophosphamide for 8 cycles. Her last chemotherapy got over on 25th March 2021. 7 day later she developed fever, and got Covid along with Dengue. She was admitted in a hospital for the same and recovered from it, but meanwhile her radiation has gotten delayed. Since 3-4 days she's complaining of pain near the angle of Mandible. I am getting a bit worried. As we are in lockdown nd my mother is afraid and reluctant to step out from home and visit any hospital, I was wondering, 1) For how long after chemotherapy can we safely delay Radiation? 2) when do we need to start the radiation? 3) when can I safely vaccinate her for covid?