no advice to give, except perhaps each of you giving the other a little space tonight.
hubby and i will have similar arguments when the cable/internet goes out, but for us it's largely because he thinks resetting the cable box/modem will fix EVERYTHING and me thinking that every hiccup is a scenario where we will be out of cable for days on end and I won't be able to work.
To me, it sounds like your router needed to be reset, which is absolutely something Spectrum or any other cable company can do remotely.
It also sounds like maybe your dad doesn't want anyone coming into the house to see all of the various...improvements that he's made with all his various splitters and in-out-out-in connections? My dad would get seriously grumpy when we would do things for him that he figured he could do himself. Maybe that's a generational thing.