This does not hold true for Harry's parents, who, while trying to hide, still died resisting Voldermort and who, like the Lupins, left an orphan behind.
[Mr. and Mrs. Wesley were also in the thick of the fight and they also survived.]
By the way, I think Mrs. Weasley was pretty much written to be the "perfect" mother-figure in the series... she could (apparently) pull food out of thin air, she could always find a place for anyone who needed one, her biggest fear was harm coming to her family, she would forgive any wrong done by any of her children (she was the only one who never said anything bad about Percy, and she never gave up hope that he would come back to the family), and she would do anything to protect her children, from annoying them incessantly to putting down the baddest warrior-witch out there, if that (w)itch dared to threaten her children.
Commentary on feminism, anyone?