Alcohol should be avoided, particularly in the case of alcoholic fatty liver. A good rule of thumb for fatty liver patients is to follow a diet plan that consists of 20-30% protein, 60-70% carbohydrates, and 20-30% fats. Fat intake is the most important and should never exceed 30%.
It is possible to go to jail for retail petty theft because the maximum penalty is 1 year in the county jail, but it is extremely unlikely that you will be sentenced to any jail time at all. As it is your first offense and the property was recovered, you should be offered a chance to attend a diversion program, if your county offers them.
Vehicle Theft, Penal Code 10851, is a wobbler, meaning it can be charged as a felony with a maximum prison sentence of three years, or as a misdemeanor with a maximum of a year in jail. There is no way to know what your cousin's sentence might be.