Door blowing open in Shop

[Wdoc5]

Hi,a shop door keeps blowing open in high winds I have fully released the roller that holds the door in place at present. the owner does not want a std mechanical door handle & they think they want a door closer. I adviced they are for closing the door & are set to allow easy OPENING of the door & will not stop the high winds from opening the door. ? what should i do :shock: