She would be the same relation to you as she is to him.
a cow
Your son would be the uncle of his brother's son.
your second nephew
your step niece,,, if it was your brothers own daughter it would be your niece, since its his stepdaughter, than its your step niece.
They would be cousins, once removed.
Yes, you would be the step-nan (or step-grandmother) to your granddaughter's step-brothers.
they were brothers !!
The brothers of your husband are your brothers-in-law.
No relation.
No, they are of no relation.
step brothers
If your niece's is by your sister but the brother is by your sisters new husband & another woman there would be no blood relation. If not then he's the nephew