Is there anyway this isn’t a half sibling?

I think I am in denial and I can’t imagine keeping a secret like this for over 40 years.

I have googled, I have been on Reddit, I’ve gone to the cM sites. Is there anyway this is my full brother?

I think I am in denial and I can’t imagine keeping a secret like this for over 40 years.

I have googled, I have been on Reddit, I’ve gone to the cM sites. Is there anyway this is my full brother?