Not gonna lie, that's either a very specific card company and/or a very awkward one, because reminding stepchildren/adopted kids/orphans that they're not being raised by their biological parents sounds like a slap in the face
his disappointment is akin to receiving a (super powerful) gift card for Christmas? Onee-san, he wants a meaningful gift or a romantic experience, something to show that you paid (too much) attention to him!