One cannot declare something as harām unless it is explicitly mentioned
in the Qur’ān. The Word of Allah says that consumption of alcohol, as an edible,
is harām, when taken in its intoxicating form. I would be trespassing my
boundaries by telling you that it is harām for your friend to work in such a
place. However, the Qur’ān (5:3) has directed us to not co-operate against evil
if we are able to.
Thus your friend should only work in such a café if he has no other option. In
case he has earnestly searched for other venues as seems to be the case, and it
is out of utter necessity that he has accepted such an employment opportunity, I
would sympathize with his circumstances, and on the same, keep reminding him to
immediately shift to another job as soon as he gets one – without any delay.
In short, your friend should continue to work if it is a deciding factor between
education or not, which is an important and valuable asset for every person, but
as soon as he discovers a more desirable means of income, he should give up his
current job. Meanwhile, he should pray and stay determined not to consume any
amount of alcohol.