Welcome, Viktor.
If your main goal is to set up a small home shop that will not only serve to carry out household projects but will also call to mind memories of your grandfather for you and your mother, that is an admirable sentiment. I wish you well in carrying out your aim. Since your grandfather sounds as though he was a serious machinist with many skills, it may be that he did not put a lot of emphasis on restoring tools, although he would probably have been careful to maintain his tools in good working condition. That would be a good guideline for you to follow. Do clean his tools, lubricate them, and ensure that they are in good working order appropriate to the period during which he used them. From your original post, it sounds as though that is what you are going to do. Perhaps at a later time you can carry out the research and other tasks that would be required for a full and accurate restoration of each tool to original condition.
-Marty-