Ast (sgot) is 2494 u/l (normal range is <50); alt(sgpt) is 2363 u/l (normal range is <50) and bilirubin total is 4.51 mg/dl. how serious is he?

It depends: How does he FEEL? If this is simply acute hepatitis from a virus or a medication, he may end up fine. If it is from alcohol, then he is in serious danger -- if he recovers, there's still the behavior that caused this in the first place, itself deadly serious. If he is systemically sick and this is "shock liver", the treatment is that of the underlying illness.