Truck does not start and the headlights do not turn on?

My dad is trying to help me fix my late husband’s truck. He found out based on my description of how the truck sounded when it was cranked that the timing was off by 1 tooth. He fixed the timing problem. The other problem is that someone had cut the battery terminals in half and removed the battery. He got a new battery and replaced the cut terminals. The fuel pump can be heard when the key is turned. But the truck won’t crank. The headlights won’t come on with the key turned on. We are worried it’s a wiring issue since the battery terminals had been cut. We checked to make sure all the relays and fuses were good. We have no reason to suspect the starter is bad. While changing the timing belt my dad also put in a new water pump. What could cause the headlights not to come on and it not to crank?