I'm pissed off at my deceased family member's wife because she got pregnant with another guys kid 15 days after he died
Wow, was there cheating going on?
She was probably cheating the whole time.
I see how this is upsetting, but people handle death in different ways. There is nothing you can do here, so try your best to focus on what will make your own life better
What I can do? I can't control her.
You have a valid point. Perhaps you can have a conversation with her about what is going on and express your concerns. It might be difficult, but it's best it gets sorted out as soon as possible.