My FIL always seems to ask about the price of everything we buy . Just nosy I guess. Recently he asked my husband how much money we both got each month and how much we had in savings . My DH simply gave him the information and I was pretty angry, although I waited until we were alone to tell him how I felt . He said that he has " that sort of relationship " with his dad and just because I didn't it didn't mean that he couldn't tell him stuff .I pointed out that these were " OUR " finances ( all our money etc. is in joint names ) and not just HIS financial details and that I did not wish his father to know the details . He couldn't see what I was making a fuss about and I'm not really sure myself why I feel so strongly except to say that I would like to have some privacy .... things that are only just between us two . Interestingly he said that he wouldn't want our two children to know our financial details . Also interestingly SIL and BIL , until recently have kept their financial details to themselves , SIL always pleading poverty . As a a result of a family problem last year he found out about their finances and was quite surprised that in fact they were better off than he had been led to believe.
Sorry to go on and on but ..... he always gives us little " lectures " about how lucky we are ..... if we've been out for a nice meal for example . It's as if he thinks we are unaware of this and must be told like children. It wouldn't be so bad if he actually ever gave any money to charities but he never does .