Here’s some ideas for alternatives before surgery. The suggested are on page 9 but the background on carpal tunnel is worth reading.
Have you tried vitamin B6 from rich food sources?
If he’s really inflamed finding the reason for the inflammation should be the number one focus. Serratiopeptidase is great for inflammation and will reduce pain associated with inflammation but it’s just a band-aid on the problem until you find what is causing the inflammation and stop it at the source.