Pact of the Chain Warlocks may allow their loved ones to attack instead of them when they perform the Attack action (focus: mine):
They learn the spell "Finding Familiar" and can use it as a ritual. The spell does not count against your number of known spells. When you cast the spell, you can choose one of the normal shapes for your familiar or one of the following special shapes: imp, pseudodragon, quasit or sprite. In addition, if you perform the Attack action, you can do without one of your own attacks so that your friend can use his or her own reaction to attack.
And the spell "Gasform" says that its target can not attack (again highlight my):
In the form of a misty cloud, the target can not speak or manipulate objects, and objects carried or held in its hand can not be dropped, used, or otherwise interacted with. The target can not attack or cast spells.
My question, then, is whether a pact of the Chain Warlock in gaseous form can have its known attack. The spell does not say that the target can not do the attack, but that it can not attack, and in that case, the sorcerer will not make the attack.