1. 我爸爸的姐姐還需要提供什麽材料? (她是公民,不過已經退休長住內)
-Same as she did for I-130 filing.
2. 我爸爸現在B2 VISA 在美國,讓他延期後留在美國辦會不會更方便,還是最好回國去辦?
-If he can extend his B-2 status until the priority date is current (排期到), then he can file I-485 within US. Thus, it is very convenient. Otherwise, if his status expires before 排期到, he has to leave US and apply for the immigration visa in China.
3. 他們B2 給到6/15/2015,priority date 是7/2/2002, 現在(March)F4排期是5/15/2002,有必要B2延期嗎?
-Has better extend it in May if you find the priority date will not be current in June.
4. 2002年申請書上隻有我爸爸的名字,排期到後可以讓我媽媽和他一起辦嗎?
-Yes. If your mother is in US at that time, she can file I-485 together with your father. If she is in China, then she has to apply for the immigration visa in China (your father also had better apply for the immigration visa in China together in this case, thus you mother will get the immigration visa quickly).
5 . 費用大概是多少,如果爸爸媽媽一起辦,需要請律師的必要嗎?
-Up to you. It is very simple procedure if they are in US to file I-485. It is a little more procedure to apply for the immigration visa in China (not difficult).