Water dripping through firewall behind the dash

Professor Fate said
1.) Failed wiper pivot seals
2.) Plugged cowl drains
3.) Rotted out lower (inner) cowl
4.) Windshield gasket/seal leaking or incorrectly installed

Nailed it!

Bewy said
If the heater core leaked, anti-freeze can corrode the f'wall.

Would have to have been a pretty impressive heater core leak for the firewall on the passenger side under the heater core to be so rotted it’s sending water all the way to the opposite side at the steering column and pedal box.