We have 2 Bruder trailers where the hitch pin broke off the same way. I searched for a replacement and found the model this one is remixed from, but in our case it appeared easier to not to drill the hitch part out. Instead I modified the model so it fits, by cutting out a semi circle at the bottom. This way, it can be slid in from the top and if it breaks again, easily pushed out from the bottom in case of need for replacement.
See the second photo with the green trailer the failure case for for which this model works well.
German: Dies ist ein Ersatzteil für den Pin der Kupplung bei Bruder Anhängern oder Fahrzeugen.
Printed upright with some paint on supports. It might be more sturdy if printed laying down, but haven't tried so far.
The author remixed this model.