Would like some perspective please

Hi folks, I am 26 years old and about 4 years ago I found out by accident that I have an older half-brother. I learned that I can seek him out through a court intermediary, if he's interested, of course. I think he would be because I also learned that he wrote my mother a letter a few years ago. The problem is this: When I tried to ask my mom about this, she denied the entire thing even though I know it's true. I imagine it's part of a coping mechanism because she was raped at a very young age and was forced to hide away during the pregnancy from her family. I can't imagine the kind of pain she went through. I have seen what I now think of some PTSD manifest throughout her life, getting upset to the point of yelling and throwing things for little to no reason. This very rarely happens now (according to my Dad, maybe once or twice a year), but growing up my siblings and I were always nervous of tripping her up. As far as I know she's never gotten any therapy for it and prefers to hide it under the rug (like how my siblings and Dad like to do most things, very much unlike myself who likes to talk things out in the open). I want to contact my half-brother. Not only because we have significant medical history (grandpa died youngish and lots of chronic conditions manifested in my mom and her siblings--his bio aunts), but I am I suppose naturally drawn to the idea of knowing someone else who has half of the same genes that I do. I only have sisters and it was quite a shock to learn that we had a brother. I in no way am trying to assume that we'd have a good relationship or even one at all and I can't imagine the pain he has gone through either...(or possibly none depending I suppose...) He is in his late 30s or early 40s at this point, as well. My concern is my mom. Even though I am married, I am under no illusions that if he knows my name that it would be very easy to track down my maiden name and subsequently my mom. When I tried to talk to my Dad about this (he basically refused) 4 years ago, he didn't want to upset the apple cart. After talking to a few relatives, I understand that his first priority is to protect his wife from being upset. I can't make my half-brother not contact my mother and I'm wondering if it's even cruel to find him but then tell him that he shouldn't contact my mom--possibly ever. My mom apparently told my grandma that she didn't contact him because she had "young children." We are all grown up now (well, one is 22 and the other is 14). Ironically, through a series of accidents, both sisters know about him, so everyone knows about him but not everyone knows that everyone knows. The 14 year old is mature beyond her years and although upset about the circumstances (naturally), she seems to have accepted it and even sees now why my mom acts the way she does sometimes. ...................... Thoughts? I know no one can give me a "right" answer. I know that there would be risks if I tried to contact him. I feel like we have such a short time on this Earth and I would like to try.