Science can't touch god
It maybe true that Science cannot touch God, but perhaps a god needs to be selected as the true god for science to "touch". This argument goes no where towards stating that a god exists, especially a specific god of ones preference.
It may also be valuable to realise that Science comments on the natural, not the supernatural. and science has nothing yet to prove the existence of a God -- as much as famous apologist's like to argue, nothing of the sort is true.
Presumably when this argument is made, the user will mean either physically or non-physically (obviously). so to rule out these possibilities it may be useful to ask what they mean precisely, this will help identifying any meanings that are unknown and help to stop the possibility of 'moving the goalposts'.
If the user means physically then this will obviously mean nothing as God is not meant to be physical and science technically isn't either. this doesn't prove anything whatsoever. If they mean non-physically then they may be refering to the notion that science has nothing to say on the truly supernatural. This is relatively true, however, if saying that "you can't prove my religion wrong, so my god is possible to exist" is the argument being made then it may be fitting to raise the notion of them considering every other religion ever conceived -- hinduism, islam, pastafarianism, catholicism, christianity, or any of the ancient religions that have been wiped out it would seem. If the user of the argument does not want to for any reason then ask why, the argument they presented is equally valuable to every conceived deity and should not be used only for a single one of preference.