Hi I thought it was me who tackled stock repair jobs like this one. Any way I use a technique that I have found works exceedingly well in these cases and up to now non of the guns I have repaired have failed in use so far and some have been in use now for some twenty five years but here is always a chance one will.
My method is to clean the break with Acetone and re glue all the parts with an Epoxy adhesive then when all is set and to make sure I leave the stock for a week for that to take place. Now working from the trigger guard slot using an engineers end mill in a milling machine I make a deep slot that runs from the trigger plate through the wrist to the end of the trigger guard slot, the slot you cut must be no wider than the trigger guard its self and when it is screwed in place it covers the added splint. Now you can insert a wrist splint into the slot I have used Stainless Steel, Brass, and Marine Ply if any inletting is required all held in place with Epoxy Adhesive though I will emphasise the slot and splint do have to be a good close fit.
I am not saying this method will work in this situation but it is another method of solving that perennial problem of a stock broken through the wrist.
Good luck with what ever you decide to do.
Damascus
