For most people, the answer is “I don’t know.” Same goes for dad’s will. In fact, most people do not know whether their parents have even made wills, and if so, what is in those documents and where they might be.
A will is only useful if you know where it is. There are so many times that we as lawyers receive emails asking if we are aware of a will for someone who has died, because the surviving children just don’t know. Dealing with an estate where there is no will is substantially more difficult than where there is one, but having one is only have the battle: you also have to know where it is. If you have a will, you should talk to your children about it, and if you have parents, you should talk to them about whether they have wills, and, equally as important, where they are.