What kind of lawyer do I need to handle my late father's stocks and bonds?

My Dad passed away in March of 2008 and my mom honestly believes that only my brothers can make lawyer decisions and such. Well it has been almost a year and nothing has been done with the stocks and savings bonds that are only in his name! I am afraid that my mom will lose everything my dad worked so hard to have. We are talking about quite a bit of money! My question is how much time do we have and is there anything I can do legally to speed up the process? What kind of lawyer do I need?