Short answer - 'no' they aren't at all suitable. The holes in the grids are far too wide for gerbils and cages aren't appropriate housing for gerbils anyway. They like to dig so they should be kept in a glass tank to allow them to fulfill their burrowing instincts. Keeping them in a cage will result in either the gerbils gnawing their way to freedom via the plastic base or they will get substrate everywhere as they try to dig in the plastic.
My pair live in a 30" long glass tank but I'm hoping to upgrade it to a 4ft tank eventually.
A good gerbil forum to 'signpost' your friend to if they have internet is this one:
egerbil - the website has a lot of information too. It's an excellent source of general information on social groupings, housing and diet.