open circuit?

House built 1954 w/gr ma apartment w/its own breaker box. All original wiring. Fuse boxes replaced with breaker boxes by licensed electrician in 2012.

Three days ago while she used hair dryer in apt bathroom, it stopped. No power at GFCI socket. Breaker did not pop. Also not everything on that circuit stopped working. Just everything on that end of the circuit (bathroom socket and two hardwired ceiling lamps).

The bathroom GFCI socket test and reset switches don't work. Don't know if the GFCI was working or not. Removed it and no power at the bare wires. Both ceiling lamps still not work w/socket removed.

Removed the two wall ceiling lamp switches and looked at the wires, wire nuts, screws and all looked fine. Flipped the breaker back on and tested again. No power at socket and one lamp turned on for less then 1/2 second then went off by itself. Checked and bulb still good. Moved switch and wires to see if it would light again. nope. Turned off breaker and put switches back into wall and wire nutted the exposed socket wires before she got home. Then the two lamps worked and socket wires here hot.WTF?

So, the next day I removed the switches inspected wires and replaced the wire nuts, replaced small wire section, cleaned and re attached wires to switches. Installed non GFCI socket. Both lamps and socket still work. Yea!!!

later that day and the next day lamps still work, socket not tested. next day same, then later that 2nd day, both lamps and socket dead.

All switch and socket boxes in house and apartment are two wire, except as shown below (this is the apartment bath socket and ceiling lamp and its switch). Also, the fridge in the apartment has that 3rd red wire that attaches to the socket box behind the fridge. In the apartment breaker box there is one red wire attached to the neutral bar, as it was in the fuse box.

https://imgur.com/a/GYmuSca

Ideas?