Anything can be fixed. And there are ways to limit how much the repair will change the sound of the violin. But like anything, it is a matter of skill and patience. If there are lots of cracks, then you have lots of work. There are books to instruct. There are luthier supply businesses to provide the tools and materials. If its your first repair, you should ask yourself how important it is to restore this violin. If it must be fixed, bring it to a recommended violin repair shop. If you are just curious about how to repair and dont mind the real possibility that it wont be fixed right, then read up, buy your tools and materials and have fun.