I'm 40 and I just found out my Father isn't my biological Father

I am so sorry that you found out that way. If I were you I would contact your biological father for sure. You only know what you have been told which may or may not be true. There are two sides to every story. You don't really have anything to lose. If he doesn't want communication then you haven't lost anything. If he does then you get some answers. Best case maybe you can have a relationship with him. If he doesn't want to be a part of your life, you should tell him you are interested in at least getting to know your brothers.