How to be a Perfect Stranger

Our neighbour across the street has been battling cancer for the past year and is apparently losing her battle. Her husband told us Saturday that they have stopped treatments and that she is now at a palliative care facility.
These neighbours have lived across the street from us for several years -- I don't know how many -- and we have exchanged pleasantries over the years. The awful thing is, I don't even know their names. I'm sure they told us but we've always just politely asked how ia your husband/wife, how are the children, using generic family member wording.
So I did a reverse 411.ca lookup and found a name. Is it his name or hers? They have talked about "back home" but have never mentioned exactly where "back home" is, although I could venture a guess. I don't know their ethnic or religious background. And in politically correct Canada, that is a question that one does just not ask.
I am expecting a funeral in the near future. So even if I had "How To Be a Perfect Stranger", a book which explains proper etiquette for various cultures' and religions' lifecycle events (births, weddings, funerals), I don't know which group they belong to. When the time comes, I can only hope that my actions will not offend and not add to the family's sorrow.