How could a mom not want him... He's perfect to us

Re

My s/o and I are expecting a little girl in April and we are raising our 2 week old grandson. His dad lives with us and is helping a bit but for the most part its all us. Even though I dont understand how this perfect little boys mom doesn't want him, we refuse to negatively bash her. It takes a strong person to say I cant do it. We are just grateful she asked us, his grand parents to have him. Instead of giving him up for adoption. We have had him since he was 2 hrs old and we wouldn't change a thing. We would do it all over again if need be... Isn't he precious 💙