When someone passes away, people don’t quite know what to do so they will usually send gifts of food, and funeral flowers to show how sorry they are. They do this because they need to be doing something. Take the time to write these thank you notes, it doesn’t matter if they are several weeks after the funeral. Nobody expects you to send your thank you notes right after the funeral.
Keep the cards from the flowers, so you know who you need to write thank you notes to after the funeral. Be personal in the thank you notes, let people know how much you appreciate their support.