My Dad had Sciatica when he got older and it really messed with his life. I’m sure it helped put him in a wheelchair much earlier than might have been and shortened his life.
A while back I started to have Sciatica symptoms and it really effed with my sleep. I tried everything I could think of but nothing helped. Then one day my sweetie brought home a new stretch from yoga class that I was unaware of. It’s called the Supine Pigeon Pose. I did this pose along with the rest of my routine for perhaps a total of 15 minutes in a few days. It was friggin miraculous my Sciatica just disappeared! I’d been tormented for months and now 15 minutes of exercise had solved my problem. Now I do it 2 or 3 times a weeks and the Sciatica has never returned.
You might pass this one on to your mate. As per usual with yoga poses I’d advise to start slow and be stretched before trying it. You don’t want to pull anything. It may not help him, everyone’s different, but it’s worth a shot.
Cheers
PS I don’t do it like the video. The top picture gives a good picture of it. Just pull your knee towards you and that gives a great stretch. A few minutes and do the other side.