What is wrong with the lights?

Here's what I do not understand, If you already called the electrician and he inspected the circuit...Why you asking for advise...? Did he did the job, or you did not allow him to do it...? To answer part of your questions...the lights switch does not require a ground to operate, but is optional as security. Light switches operate by closing one NORMALLY OPEN circuit wire to allow voltage to those lights. You can perform a test by running a loop between the switch pair of wires that are connected parallel. If the lights turn ON, then replace the switch. If this does not do for you, then your electrician was right when he said that there's a most serious issue to take care. You must call back that money hungry electrician again...! Good luck...!