They should do it when they need to. Right now they can't make and distribute enough cars to satisfy demand. When they can, they should advertise to start increasing demand.
I think there's some argument to be made that they should be doing brand promotion advertisement just to counteract all the FUD in people's brains. I wouldn't have agreed with that six months ago, but its gotten a little crazy... so perhaps now. But the decision about how to most effectively do that probably needs a little more market research than some web polls. For example... who exactly are they trying to reach that aren't already ok with the brand? Rolling coal rednecks? Why bother? Millennials? It sounds to me like they're already convinced without advertising. Maybe his strategy is that the millennials will keep growing up and the old people will keep dieing and maybe industry growth will happen by attrition a the proper rate?