First - lots of adult drama seems to be in play, but let's power through that
Scouts are the best recruits for Scouts. The best way to get boys who are not involved is PROGRAM. Not advancement, not meetings, not citizenship, etc etc, it's PROGRAM. Get your 3 active scouts to clearly set a calendar of OUTDOOR PROGRAMMING. That is the selling point for other boys to engage, what will THEY be doing, what is in it for them. Go Do Stuff. Get the dates set and get a plan to go do things. Not sure where you are but that is what will get the boys to show up.
Canoeing, kayaking. hiking