Perl 6, 25 bytes

{$^a==$^b|5-$b|$b-5|$b+5}

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Port of @Arbo's solution. This uses the Any Junction rather than checking if a is a the list. Technically, ^ could work as well.

Explanation:

{                        }  # Anonymous code block
 $^a==                      # Is the first input equal to
         |    |    |        # Any of
      $^b                       # The second input
          5-$b                  # 5 - b
               $b-5             # b - 5
                     $b+5       # b + 5

Perl 6, 24 bytes

-1 byte thanks to Grimy

{$^a-$^b==5|0|-5|5-2*$b}

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This uses the Any Junction but technically, ^ could work as well.

Explanation:

{                      }  # Anonymous code block
 $^a-$^b==                # Is the difference equal to
           | |  |        # Any of
          0 
            5
              -5
                 5-2*$b