You shouldn't convince anyone to invest in bitcoin.Simply because it is a financial investment and they may lose money and if they do then they will blame you.What you should do is try to explain them pro's and con's of investing in bitcoin and let them decide what they want to do on their own.No matter how hard you try to convince them they won't use bitcoin unless they learn about it and experience it.Some people will never use bitcoin because they simply not able to/try to understand how it works,some people think bitcoin is too advanced for them,some people think it is illegal and government will be after them if they use bitcoin You can't convince these types of people.