Sympathies, dear lady! We had echoes of your father with our late parents.
* Holding down Ctrl-V when pasting — my father.
* Using speaker phone ALL THE TIME — Deb’s mom. Mom also had the TV on 24x7, especially (or so Deb reports) when her daughter called. Requests to turn off or mute the telly always caused crises because the remote would spontaneously vanish, or the buttons stopped working.
* Discovering cool “new” phone features — my mother. Sometimes rediscovering them, as her dementia worsened.
I ended up prying the left Ctrl key from my father’s keyboard. He would hit Ctrl-A when he meant Shift-A, all the text selected (he was staring at the keyboard, he never noticed), he would type the next letter and “text just vanishes for no reason!”
OTOH your dad still comes across as a lovable teddy bear (at least in his daughter’s eyes 😉). (Love those selfies, btw!) My father’s descent into dementia included his personality reverting to the jerk he’d been when I was a kid, both to me (but I could handle it; DEB: Jackster, reverting to childlike behavior was not “handling it”!) and to Deb (who was devastated, since my father had always been wonderful to her and he’d filled some of the void after her own dad died). With a loving, caring daughter like you, I expect your dad will be lovable to the end. (Exasperating, on occasion, but lovable. 😊)