2003 Hyundai elantra won't start

So my boyfriend started our car this morning to go get gas, the gas light was on, but he forgot something so he turned around. When he got back in the car it wouldn’t start so he went to get some gas to put in the car but the car still wouldn’t turn on. Next he tried charging the battery but nothing happened when he tried to turn the car on. I made sure the car was in park and his dad checked to make sure the battery, a year old, was connected properly, nothing worked. My boyfriends dad says it must be the starter but I would like a second opinion. Thanks!!

Does it crank? Or just click?
Do the dash lights or headlights go dark while trying to crank?