Am I obligated to ask about my mother, and would my not asking about her be considered a severing of kinship ties, especially since she left the home without her father's knowledge and took my siblings against their will, and my father did not wrong her, and she has not asked about me?

If the mother leaves the house without the father's permission or a legitimate reason, she is disobedient (''asiyah'') and rebellious (''nashiz''), but honoring her remains obligatory, and maintaining ties with her is among the greatest acts of upholding kinship (''silat al-rahim''). You should advise her gently and remind her of Allah, and that her action is contrary to Islamic law. If she took the two brothers without the father's knowledge, she has also erred; for custody is a right for both parents as long as the marital relationship exists. It is recommended to supplicate for her righteousness.