Making Grandmother Happy

Short history, my grandfather died in 2020 of a stroke before the pandemic and my now widowed grandmother 60 came to stay with me thru the pandemic lockdown and we missed getting Covid and she decided to stay with as she didn't to be alone. I'm an electrician (25) and work for the local hospital maintenance section (shift work). Not great with relationships but have had my moments. I left school (16) to train as an electrician and lived alone till my grandmother came to live with me. My parents live in the next state and my younger sibling is living there also. Anyway, with the lockdown finished we got back to something like normal and then in January 2022 my grandmother had a sort of seizure not a stroke. She recovered and nothing of note was found by the doctors, she seemed to have fully recovered. My parents and sibling had visited, and my mother (nurse) 43 stayed a fortnight longer to make sure her mother was fully recovered. About a month after my mother returned home my grandmother joined in my bed and wanted sex. It was a shock to me at first, she was insistent about me fucking her. So, to make her happy I fucked her twice that night. In the morning, she told she was happy I'd fucked as really needed fucking. I replied anytime and thought it probably wouldn't happen again and in the weeks that followed she didn't ask for sex again. Then on a stormy night she again joined me in my bed and wanted sex again and I fucked twice like I had before. But next morning she wanted another fucking and then no sex for the weeks following. At end of July, I got home from work at 2am and found her sitting in lounge in the dark. Totally naked and she was waiting for me to fuck her again and we went and showered together, and I fucked her in the shower and again my bed. In the morning, we fucked again and then showered together again and had sex again showering. I went off shift a couple days later no more sex, till I was off duty for 3 days. My grandmother wanted sex everyday I'd off and nothing wasn't tried (vaginal, oral and anal). She became a regular in my bed, no more than 3 days and nights in a row without her joining me in my bed. In June 2023 my parents separated, and my mother came to live with us and got a job at the same hospital as me. She didn't oppose the divorce and it went quickly; while was working I was fucking my grandmother. My grandmother got ill March 2024 and was put in hospital for 4 days, not a repeat of the seizure a viral infection. Anyway, I was off at the same time as my mother, and I walked into the bathroom, and she was showering, and I joined her. It was a shocked to her at first, but she let me stay and feel her up. I fucked her in shower and then in my bed and she is now regular fuck for me also. Neither knows I'm fucking the other.