Hey. I have the same problem as your friend. It's very frustrating you feel as though you never rest because automation never occurs. I mentally feel like i'm always awake because i'm constantly thinking or doing. I've watched television in dreams, i've read in dreams, and yes I have tried sleeping in dreams. But it just feels like i'm still in the waking state.

Anyway I've found that I cope with this by varying my level of lucidity. You should see if your friend can find a way to tone it down. Let everything else exist and try to become reactive to their dreams. I often keep the majority of my lucidity at bay unless I begin to enter a nightmare in which case I tend to kick things into full gear to put an end to it. So perhaps that will help. My only other suggestion is drink heavily because the simple and dark blackness that a drunken nap can provide is blissful but absolutely terrible for you unfortunately.

For a bit of background I began lucid dreaming when I was about 2-4. In a nightmare there was a strange black and enigmatic apparition with enormous teeth and red eyes. Not very imaginative but for a child of that age it was absolutely terrifying. In my fear I split the creature in two mentally and a blinding white light emerged from the bifurcated area and I woke up. Lucid ever sense.