1. we never saw him again-> he 2he learned to drive when he was eighteen. -> He was

We never saw him again, and his absence left a void in our group.

He learned to drive when he was eighteen, a milestone achievement for him.

We never saw him again, he disappeared without a trace.

He learned to drive when he was eighteen, so he was finally able to get his driver's license.

We never saw him again, so he disappeared from our lives completely.