Everyone needs to sit down and take a look at what your in-laws furture will look like. How will they be cared for when the time comes.
My former mother in law financially supported my ex's siblings - in a very big way (holidays, shopping, even bought a condo for two of the grandchildren). Today she has taken ill and is waiting for plaacement in government run nursing home because those same ungrateful children/grand children won't offer up a dime.