Well fiber's a bitch to digest but if you cut it into small enough pieces it'll basically be like eating really thick and hard asparagus which wouldn't cause too much issue.
Also there are ways to make edible clothing, with the right recipe it can even be tasty. Which is what I recommend you do and what I expected him to do. Hell even making one of those shoe-looking "cakes" (that are usually almost 90% fondant, which, ew... Seriously please people do yourself a favor and use buttercream whenever possible) would've sufficed. It would've made him a cheeky cunt, but I like cheeky cunts.