Doesn't "as for" have the same meaning as "regarding" here? "As for this boy, he is drinking" should also be an answer.
i second that
I'm pretty sure that by itself "il boit" implies alcohol, just like "he drinks" in English.
'As far as this boy is concerned, he drinks' should also be allowed because 'regarding him' and 'as far as he is concerned' has the same implication.
Does it means that the boy drinks alcohol?