How do I deal with insensitive family members when it comes to my infetility?

It sounds like he may have been embarrassed, either about your infertility or about your desire to share with others. If so, this isn't YOUR problem, it's his. It is also possible that he didn't want you to be disappointed if things didn't work out, and have to go through having to explain that you're not having a baby after posting the positive results. What you need to do is let your brother know what it is you need from him and tell him straight up. "Bro, this is really hard from me. I need you to be my cheerleader through this and focus on the positive not the negative." Or "I want you to support me through this, even when things go wrong, and be happy for me when there's good news." In other words, tell him what you do want, rather than what you don't want. A good brother will do his very best to help you out.