I find these expectations odd. She's your ex-BOSS's wife that's passed. Someone you were not at all close with. Why feel guilty? Don't mix your professional life with your personal one. Had you still worked with him, it would be respectful to send him a sympathy card. Despite how he treated you, should not reflect the good person that you are. I don't understand why this new boss is telling you what you ought to do. Strange. He's not family nor is he a part of your current life.

You are not at all obliged to do anything. You no longer work together and you did not have a healthy working relationship with him before. So, you've done all you needed to do and you don't need to discuss it further.

Is this a really small town community where everyone knows each other? I live in a big city so I've never come across a scenario where I felt pressured to participate in my ex-boss's personal life.