This DOES bring up a good question about the movie, why did Mel tell him about his mother DURING A FREAKIN' ALIEN BREAK-IN?! I mean shouldn't they have gotten prepared to defend the house?!
Finally I hope that now you bastards know why green peace tries to defend our trees...
It is the only solution against alien invasions...
[Disclaimer: Wood only works against, wood based allergic alien races, for other aliens please use, grass, weed, clean water, fresh air, fertile soil, and all that eco-stuff.:D]