Milk thistle* (Silybum marianum) has been suggested as a general liver aid, and there's evidence it can be protective against some substances/drugs that have hepatotoxic properties (like acetominophen). Findings are mixed on whether it can help in alcoholic liver disease.

It is considered a relatively safe herb. It may interfere with other drugs your friend might be taking, so consulting with his doctor before starting it would be a good idea.

Most important of course is staying away from alcohol and limiting exposure to other hepatotoxins (including certain prescription and herbal drugs).

*makes an interesting ornamental plant for the garden too. Very spiky leaves.

I drank Dandilion tea for an extended period of time with no noticeable problem. It was in the form of roasted dandelion roots, with other things, designed as a basic beverage, not as a supplement. When I stopped drinking coffee, it was a welcome substitute.

I don't know why I stopped drinking it; guess the attraction simply waned for awhile. Possibly that could mean that the body eventually feels it has had "enough" of dandilion? I tend to not ingest most things that no longer attract me, and it probably is for the best to do so.

I make an exception for such things as my liquid glucosamine, which has a terrible, oversweetened taste which the manufacturer adds to the basic product, only because if I do not take it, I notice the difference in my arthritis (for the worse) in the same day that I miss it.

(In fact, if there is anyone out there with the ability to do a liquid glucosamine in the same formulation as the "Drinkables" one WITHOUT sweetening and flavoring it obnoxiously, I wish they would enter into competition with that company...maybe flavoring it with soy sauce or something else that is not sweet. I swear, there must be something better that could be done to make it palatable, especially since most of the population that takes it is old enough to begin to worry about diabetes.)

I have been using Dandelion greens for more than a decade as spinach as well as tea.It is good for the health of liver and in lowering blood sugar.
Here is a link with more information about Dandelion.
http://earthnotes.tripod.com/dandelion_h.htm.