My niece has a 12-year old daughter named Mary.
What is going on with Mary?
Mary got pregnant after having a summer romance.
While it is not good in many different ways, some people do have children really young. It is good to be there for them and provide help because they will need it.
I'm not sure how I can be supportive of Mary. She's my brother's responsibility.
Then maybe it would be a good idea to reach out to your brother and ask if there's anyway you can help. When young people have children, it can be a particularly stressful and scary experience and it's good to have family to see them through it.