If it was previously Helicoiled, then that sucks and if it was TimeSerted, then that really sucks. Neither are an optimum fix for tapered pipe threads IMO.
I would grind the boss down about 1/8" so that the damaged material on top is removed. Then up-size the hole to 1/4" NPT and install a brass pipe plug with female hex drive. Then drill and tap the newly installed 1/4" plug to 1/8" BSPT to finish the repair.