Translation?

How do you translate this Irish sentence?

Ce a bhfuil a mhatair san otharlann.

In this PDF, page 2,
http://www.ic.sunysb.edu/Clubs/nels/jbailyn/Irish%20problem5.1.pdf
they translate it as "Who is (his) mother in the hospital?"

But isn't the meaning of the Irish sentence rather: "Whose mother is
in the hospital?" I mean "ce" refers to the man, not to the mother,
right?

Thanks!
M.