You are not required to use the services of an immigration attorney but it is typic ally helpful. You are required to establish eligibility for the benefit requested. It is by no means gusrabteed the petition will be approved. An attorney is often helpful because he/she knows what must be submitted snd at what stage, which in turn makes the process goes as smoothly and quickly as possible.
You will not be able to file a separate petition for your stepmother. Your father remarried after to your 18th birthday, which means your stepmother is not consider a parent under United Stares immigration law. She should not simply come as a visitor. This can lead to very serious consequences. Your father will be able to petition for her upon becoming a green card holder.
Answered on Oct 19th, 2015 at 5:20 AM