I was diagnosed with Gilberts Disease after suffering from Chronic Fatigue Syndrome for a year or so. I had trouble recovering from a bout of glandular fever and had elevated liver enzymes as well as high bilirubin levels.
I was advised to avoid paracetamol in particular, and generally I do not take OTC medications such as painkillers.
I did a bit of research and decided silymarin (milk thistle extract) and glutathione would be good supplements for me. I also stayed off alcohol for about 4 years.
I would suggest detoxing your son's diet and your home - eat organically, avoid detergents and chemical cleaners packed with petrochemicals and synthetic fragrances and use low-odour paints.
Also, think about consulting a good homeopath for constitutional treatment and/or a naturopath to overhaul his diet.