Grob 103 Canopy release failure

First off, you should report this to the Federallies. The canopy frame can be opened up by carefully cutting a hole in the problem area, then replace the worn / broken bolts, then close it up by gluing in a backing plate which can be a "donut" shape. After the backing plate cures, then glue in a skin replacement (which can be the original piece ) if you were careful when opening up the frame. Fill and paint and she's ready to go. If your not comfortable with any of this, your frame should probably see a sailplane Doctor..
Have fun,
JJ