Practically anything is possible if you have a positive attitude and patience to carry it out.
Here's a stock repair I did for a friend who fell on his rifle smashing it through the lock area, arguably the worst place to break a stock. Luckily he was able to find all the pieces in the snow, and brought the rifle to me not having been disassembled. The steel furniture held it together until I got it into the shop.
This next pic is of the whole lot reassembled with AccraGlas (Brownell's) gluing it all together.
There may be other issues with an antique rifle that has been broken for a long time, and maybe even an attmpt at repair. If someone else's glue is in the break - good luck!! If pieces are missing, they can be made to fit, but it isn't as strong as a break like the one above. AccraGlas is amazing glue(epoxy). It can be made super thin to work into cracks by holding under a light bulb 'til hot, but be aware that this accelerates the 'kick over' (curing). Still there is lots of time for it to work, as normally, it requires a good 24 hours to cure. And it can be thickened by adding the flok (shredded fibreglass) to fill gaps, but again, this is not as strong as a microscopic glue line. The rifle above has been shooting strong these past four years after repair, accounting for thousands of shots.