Tama chan asking if she can sit at a piano again breaks my heart. After all the terrible things she went through, being unable to play music was still the worst of them all. After a life of dedication to music she must be really passionate about it, but still she couldn´t abandon her child, so she had to let it go when everyone rejected her. Grandma must have felt like an angel from the sky to her, providing both protection for her son and also a place where she can play music again.
Also, Souya being based as always, instead of learning how to live with a kid, he just built a secret base for himself and his buddies, kids not allowed. This is how the Meijin champion does things, everyone.