He wasn't that tolerant of alcohol, and also had gall bladder disease (his gall bladder was eventually removed). As bile is important for fat digestion, avoiding excess high fat foods could be a good idea. My dad always had a problem with high fat foods, but they bother me too and I don't seem to have GS (my LFTs have always been normal).
My mum was talking the other day about how much energy my dad had when he was young - and he was known to have the condition from a young age. Back then, they tried to treat it with phenobarbitone, which boosts liver function. It's also hepatotoxic, and is a sedative, so he have that up after finding it causing him trouble when driving.