I've read this lovely tale on other sites and even now it moves me to weep.  Whether it was Lily or Albus, or both together, that crossed through the Veil to be sure that Severus finally found his rest, it is a blessing it was done.  Or perhaps it was some gracious deity bestowing long denied mercy - in the Biblical reference "Well done, thou good and faithful servant - well done."  This one goes to my favorites, on every site where I've read it.