Dark skies explained
Like in Poltergeist, this is a film primarily about a family losing their house due to financial difficulties.
It also states that kids that hang out with older problematic kids are doomed — their sexuality is or may get twisted, and thus they are either ‘lost’ figuratively or will disappear from the sight of family, taken by ‘the others’ (that kid who is never home, smoking dope with other ‘lost’ kids).
All this was caused by the disempowerment of the father figure. Unemployed and unable o provide, he also loses the ability to be a proper father. The woman, having to provide, loses her mind. Hard to think of a more gender-structured social organization.
The aliens role is the same as the ghosts in Poltergeist: to bring the strength within the father (he gets a new job, he gets his guns, he pulls the family together).
The boy, however, has to die, since this is a cautionary tale for young parents. Do not let it happen in the first place.