Its very sad, the upsetting part is he always is paranoid and thinks we are hiding things from him so when he asked about his folks accusing my husband of knowing something was wrong and not telling him thats why we decided to tell him the truth and he took it so hard that we just don't know what to do if it comes up again. Would love to hear from anyone who might have gone through this problem. Always on edge concerned about the right or the wrong of this whole mess. Excuse it that sounds harsh, but there are days when it just feels that way. then we have the days were were blessed with a peaceful Larry.
When my mother came for a weekend she asked where my dad was. He had died several years earlier but I could see that wasn't what she needed to hear. "He is having a poker weekend with his buddies. And you and I are having a girls' weekend together." When she later asked if she could call him I said, "He wasn't sure which home they'd be at when, but he does have my phone number and he promised to call if he needed anything." Somehow we got through the day. The next day she was relaxed and not anxious, and we even discussed the fact that we were both widows!
I think you need to judge what will be best at the time the question comes up.
And don't worry that you've done the "wrong" thing. Your answer may cause some distress but it isn't going to do permanent damage. Do the best you can, learn from each experience, and move on.
From what I have read on the forum, it is best not to tell the person who had advanced memory problems that someone has passed, otherwise they will grieve all over again like it was the first time. Best to make up an excuse like his parents were visiting friends, etc.
My Mom [98] went through that stage, asking about her parents and siblings. They had passed years ago, thus I was making "therapeutic fibs" each time Mom asked where they were.