Unfortunately, I do not have good news for you. Take a look at this link:
Being from Mexico, under 1st Preference since he is over 21 and unmarried, you will see that the date is 18MAY93. This means that only I-130s filed on or before May 8, 1993 can now be used to immigrate to the U.S. This is a waiting line. There is nothing in the law that allows anyone to jump ahead of anyone else in line not even in the case of an emergency. So unfortunately, he still has about a 6 year wait or so until 1993 gets to 1999. Until that time, he cannot immigrate. I am truly sorry. If you pass before this date gets here, if he has a U.S. Citizen or U.S. Lawful Permanent Resident relative, that relative could replace you in the I-130 for humanitarian reasons and your son would still be able to immigrate to the U.S. Again, I am truly sorry, but there is no way to speed up this waiting line, not even in an emergency. Please let me know if you have any additional questions. I would be happy to answer them for you without additional charge, if not, please do not forget to click ACCEPT. I am not paid a salary. Clicking accept is the only way that I can get paid for helping you. When you click accept, you are not charged again and we can continue to communicate without additional charge if you have a few follow-up questions. If there is a delay in getting back to you it is either because I am answering other questions or I had to log off, but I will be back with you as soon as possible. If you would like to request me in the future, just put my name on the subject line. Positive feedback for my service to you (not the state of the law as it is) is always appreciated as well as any bonus if you think I deserve it. Thank you.