When trying to determine if a guy is right for your sister, there are lots of questions you can ask, but you should probably start off with simple "get to know you" type questions, depending on how well you already know him.
• You might start by asking when and where he was born, ask about his family; how did his parents meet, what do they do for a living.
• Then to find out more about him you can ask where he went to college, or if he's still in high school, if he intends to go to college; what did he, or does he, want to major in? Any plans for graduate school?
• Does he have a job? What kind of work is it, and what does he actually do. Does he like it? Is this part of his career plan... does he have a career plan?
• How about the future, does he see himself getting married, does he want children? How many?
• Is he responsible financially? Does he like to save some money, or does he spend everything that he gets?
We found a great web site that lists “100 questions to ask your boyfriend” most of which could easily be asked of your sister's boyfriend.
What makes an amazing male partner? Check out these 32 traits of a good boyfriend shared by Popsugar.com.