I have been doing the Wim Hof method (cold showers, breathing exercise) for two weeks and it surprisingly effective in alleviating anxiety and depression. I also feel more awake.

For context, supposedly there have been done a couple of studies [1] that show benefits for strengthening the immune system.

[1] https://www.wimhofmethod.com/science

I'd let him have his way but completely isolate him and deny him the hospital. He's over 60 and if he died, he'd be a prime candidate for the Darwin Award.