American health authorities have been investigating the safety of Montelukast since 2008.
It reported the gas canisters in his vehicle were apparently for domestic use.
In an interview with British newspaper The Guardian last year, band members said they chose the word Allah, Arabic for God, because they were seeking a "holy sounding" name.
They said they didn't realise it might offend Muslims, and had received emails from around the world from people who said they were offended.
In April 2013, Australia's Therapeutic Goods Administration (TGA) published a Medicine Safety Update article on Montelukast to alert health professionals to the risks and the need to warn patients and carers.
But both mothers Vanessa Sellick and Melanie said they were not given any warnings by their doctors."We were very, very surprised to hear that there was research out there to say that Singulair could cause such severe psychological disturbances," Melanie said.