This seems like an odd stance to take, especially when what is known about the long-term effects of THC rate them as considerably more benign than the long-term effects of chronic sleep deprivation.

I think you're overthinking it. It's not really "recreational" when it can help your quality of life significantly.

If you're expecting to die early, what have you left to lose?

Sorry for not replying sooner. She took it nightly yes (we are no longer somewhere with legal cannabis), but on the order of 5mg of THC (via edibles). It's not really enough to get her high, but it does help her stay asleep. The effect is more or less immediate and stopping takes away the effect more or less immediately.

I'd suggest a tiny pinch (<0.05g) of dry herb in a vaporizer, a couple hours before bedtime. Recurring costs are <$20/month in a legal state.

The immediate effect is quite interesting: routine tasks become less-accessible while imagination becomes more-accessible, so you think more about what you're doing, which often spawns new ideas (e.g. the desire to exercise or play an instrument, understanding both as a cyclical muscle control problem.) Afterward, the transition to sleep feels trivial.

Large doses are generally not beneficial.