Not a big deal Flower!!!!! Several ways around the issue.....Partially my fault Al....I couldn't remember exactly what size hole saw I used. I have a bunch of them laying out on the work bench, and did pick up another 1 1/2" bulkhead I had sitting around, but nothing I had sitting out for whatever reason didn't fit it.
As Al had suggested would work making a jig of sort to enlarge, the holes, but probably the simplest and safest means IMHO would be if your friend has a dremel tool or RotoZip, with a sanding drum attachment. What I would do is take the bulkhead itself and place over top the hole already in the fuge, and take a marker and trace around the outside of the threaded area leaving a template of the bulkhead itself on the fuge, and then take the dremel with the sanding drum and enlarge the holes that way......Absolutely no pressure applied to the fuge, and would probably be a tad quicker.....I will post pics of the sanding drums for reference as to what I'm talking about.