Family drama

My younger brother and his gf broke up last year. After breaking up he was told she was pregnant. They decided they were going to do an abortion until the gf decided not to. My brother made it clear he wanted nothing to do with the child. My family had been supportive from we heard the news. Throughout we have sent money, bought baby things and check up on the gf constantly. We’ve been talking to my brother throughout and telling him he needs to take responsibility. My brother then informs me that the now ex gf has been saying his family is fake ( I’m confused cause we accepted her as our own). Anyways we kept checking on her and was still supportive in anyways possible. The baby arrived a few days ago only to be told it’s a girl ( she did 2 ultrasounds and told us it was a boy). Then when we asked for pictures she said she isn’t sending out any pictures until the baby christening not even to the father. She then went ahead and texted my brother the baby needed feeding ASAP. My brother got upset and said his family cannot even get a picture and they have been supportive but she is demanding him to do things. He said he wanted a dna because he hasn’t even seen the baby. And she blocked him. Her brother called my brother and started demanding that my brother bring the baby food by a certain time. My family didn’t like how the message sound because it sounded threatening ( the ex lives in a bad area). We told my brother the only way he goes to look for the baby is if someone goes with him and if he is giving anything for the baby someone should meet him.

My brother has now decided not to sign the birth certificate or do anything until after the dna because he is yet to see the baby and my family supports him 100%.

What I want to know is if my brothers decision is right. Because I understand that she just had a baby and I don’t want the drama. But my family have been there supporting from day one even when she has been disrespectful to my brother. Should my brother do a dna?