I would just ignore. I really don't like being voluntold for things. If the email had been like, "I'm doing this, in case anyone wants to go in with me," that would be fine. But it sounds like the sender was assuming everyone would contribute, like it was the office potluck or something.
On the other hand I don't really think the additional information is relevant. I would think the email sender is being presumptuous even if the injured co-worker was a low-income single parent with twelve small kids at home. Unless there's more to the story, no one appointed Sender the Food Fairy Leader.
If I, personally, did in fact want to help out my injured co-worker, I would probably do so without consulting the sender of the email, based on my relationship with the injured co-worker.