You can catch a Hidden Ability Murkrow without the Dream World... but not in the Abundant Shrine. The Hidden Grotto in Pinwheel Forest has a 1% chance to contain Murkrow, which always has its Hidden Ability. Murkrow can be found in the Abundant Shrine in Black (but without its Hidden Ability).
The funny part is that Hidden Grottoes were introduced in Black 2 and White 2, which were released a year after this question was asked. So at the time of asking, OP's friend was a dirty liar! But fortunately for them, future events retroactively made them kind-of-right.
