Example 1
Either the Allans or Willy is in charge of snacks for the party.
In this example, is agrees with Willy because it's the closest.
Example 2
His parents or Connor has the keys to the van.
Here, has agrees with Connor because it's the word that's nearest the verb.
Example 3
Neither Latisha nor her friends have the directions to the pier.
In this sentence, have agrees with friends because it's closest.