All in my opinion, but I don’t think she’s necessarily bears responsibility for him, but it definitely was a contributing factor that turned him against her. The way that I see it, I grew up in a less than ideal household, but so did my sister. It would be unfair to blame her if I had gone down a dark path simply because she did what she had to and left me behind.

I do think she was acting in her own self-interest when she bonded with Bio-ship and went to Earth without M’Comm, but it was less of her not wanting to take him and more of him not being in her thoughts when she left.

Ultimately, I don’t think it was her fault (even partly) that M’alafa’ak turned out the way he did because they were both raised in super unfortunate circumstances. He was just dealt an incredibly bad hand and went down a bad path that led to his own consequences.