The 21-year-old singer's relative Arshiya Malik underwent the operation on a brain tumour and remains in intensive care, reported Daily Mirror.
The singer's sister Doniya, 23, has taken to Twitter to ask fans to pray for the youngster, writing, "Thank you everyone who did dua (said prayers) for Arshiya, but she still need your duas (prayers). She had 1 per cent chance! Just shows there is a god and prayers work."
Malik, who is currently on tour with the band in US, has not yet commented.