Sorry to hear that, mate. At least he recovered enough to keep up the golf!
I had similar symptoms, had no balance whatsoever and nearly decked it getting out of bed. That and my speech went, thought I had taken a stroke to be honest!
Luckily I’ve made a full recovery with no obvious lasting effects. I was 28 when I developed it from food poisoning (campylobacter from chicken on a dominos pizza, so aye, never have a dominos!!) so young and fit enough to recover well.