Yup I am pretty sure.........Well thats another case perhaps your friend did not know that it wasn't good to pray অথবা Allah had written that for her. She can pray Istikhara after her Menstruation finishes if she really needs to pray Istikhara in bitween then she can make Du'aa instead.
That would come under the same circumstance because she still hasn't had a bath (ghusl) if it is her last দিন and she nows it she can just go have a bath then pray istikhara
