Tiffanya21 - It's understandable from his Dad's perspective that he wants to protect his business. I wouldn't take it personally, it doesn't mean that he thinks that you are after the money or will screw him. He is just being cautious which is smart. So I wouldn't get upset about that at all.
Your concern about income IF something goes wrong is very valid. No judge will grant a divorce without support if the woman has been a stay-at-home Mom, but that support usually has a time limit on it (1-2 years to get your own income). It's unromantic to think about things like that it's also much better to be prepared than looking back going "what was I thinking".. Just read the prenup carefully to make sure that there is nothing unfair in it regarding support in case of a divorce. Hopefully all of these "what ifs" will never actually happen.
My husband and I didn't do a prenup since we have about equal income and assets. His parents are well off but they live in a different country so the issue never came up. Good luck!