I have a brother, but would not consider this because I know my family, and they would always consider the child "his". I don't think there's anything wrong with this option other than that. It's not incestuous at all as someone implied a year ago when I posed this question prior to my 3 OE tries.
That said, honestly, you will bond with the child or you won't. I'm not that close to my Mom, and she IS my biological mom, so who knows? Don't worry too much about projecting into the future. Worry about now.
This is tough stuff, and I'm not surprised you are stressed out.
GL to you!