The full version WAS recorded - it’s on the soundtrack album, which you’ll only find these days as a used vinyl record. But if you buy a used copy online and you have a record player, I’m sure you can work out the chords, and certainly the lyrics.

My sister has a similar story to your friend: she wanted to sing this to our mother at Christmas one year. She even began guitar lessons just to make it happen, but it never came all together, and in the end she just played it from the album as she sang it to mom.