Hi Troy,
Your friend would actually be classified as thal intermedia. Intermedias often do not need transfusions until later in life. Some doctors will change the classification to major once the patient becomes transfusion dependent. It is surprising that he was never diagnosed as intermedia for all his life, but if he has not seen doctors familiar with thal and never had a complete blood count, I imagine it is possible for him to have avoided detection.
Not having transfused has meant that he has avoided the toxic buildup of iron that comes with transfusion. If his hemoglobin level was adequate for his physical development during his younger years, then he has most likely escaped any serious problems. I would say for the most part, he is better off having put off transfusion for so many years. However, once he has had regular transfusions for awhile, he will need to begin an iron chelation drug to remove the excess iron from his body. Fortunately, there is now an easy to use oral medication called exjade that is much easier to use than the previous standard, which is the drug desferal that requires nightly subcutaneous infusions, involving a needle being inserted under the skin for about 12 hours at a time.
Your friend should have iron studies done if he has not already done so. Intermedias are prone to excess absorption of iron from their diet and can actually reach dangerously high iron levels just from absorption from food.
The prognosis in today's world is far better than it once was. I think with proper care, that your friend can live a long life. I would suggest having him join this site and learn more about his condition. We're a friendly group and a great source for information.