I didn't as I'd already delved deeply into philosophy/spirituality out of personal interest for years so I had a foundation already built.

But I did build some 'mental trip switches' from habit on some of the simple value principles I followed. When one of those switches would trip I'd remember a personal rule that conflicted with what I wanted to do when I'd be manic.

Writing things down might however be useful in his case for automatically remembering such values. What's important ultimately is not what'll be on paper but rather in your boyfriend's head.