the code is not complete, anyway you are telling to perl: fam_old is a list composed by the key tool that has Mom then Wife then Son then Daughter = 1.

hoH are covered here

Probably you want something like:

$fam_old{'tool'}  = {map{$_=>1}@terms};

$VAR1 = {
          'tool' => {
                      'Son' => 1,
                      'Wife' => 1,
                      'Mom' => 1,
                      'Daughter' => 1
                    }
        };
[download]

L*
after the UPDATE just change tool with father!