Headlights and wipers won't work.

He may have damaged wiring physically and/or grounded the battery to the chassis with the positive wire to the starter. Also, if the battery were hooked up backwards, or jumped backwards, etc, that can cause harm as well. He should start by checking all of his fuses (under hood and under dash). Then make sure his work was performed correctly. If fuses are good and he can't find a fault, time to get a professional opinion.