check the two bolts to the rad support where the ground wires attach....clean and reinstall...
Clean the terminal connections for the bulbs them selves...
CLEAN the terminals on the FOOT dimmer switch too...IF you have one....
Install 2 new bulbs,
Convince dad that the RELAY mod will work safely, provide him threads here on how it's done. GET a BOSH relay not the LMC POS kit...it's cheap for a reason!
Explain to dad that the entire load of the headlights go through the switch and are a safety concern as the wires and connections get older and resistance increases and could start a dash fire or cause complete light failure!
JM2CW
Al