As there are items that do not require attunement and allow the casting of spells through them, such as the wind fanwind fan, is it possible to have the familiar take themaintain concentration foron this spell?
While holding this fan, you can use an action to cast the Gust of Windgust of wind spell (save DC 13) from it. Once used, the fan shouldn't be used again until the next dawn. Each time it is used again before then, it has a cumulative 20 percent chance of not working and tearing into useless, nonmagical tatters.
Note that this fan does not require attunement and is a totally stand-alone tool in your familiar's hands. An octopus, rat or weasel would arguably have the ability to hold and wave such an object around.