Hi Linhi,
really I'd like to see her EASY to try to figure out what's going on. 30 mins naps sound OT to me but that's just a guess, without knowing more.
She could try for an Early BT, and hope that her LO adds on extra hours to her night sleep. If she knows her LO will not do this, then a catnap might be a good idea. But be very careful of timing as you don't want an already tired LO staying up late!