Yes you must not obey your mother in severing your kinship as this is a major sin.

My mum & her sister faught each other & my mum don’t speak to her for the past 1 year & she says that I should not speak to her or invite her to any funation in this case should I listen to my mum? Can I speak to my them without her permission

Dealings and Attitudes with Relatives | September 21, 2017 2:44 pm
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My question is what if the parents dont want their grown up children to meet thier siblings means one parental (both sides) uncles and aunts and first cousins. Because of their own personal issues. Whats on the person then? What should one do.
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What about cutting down the RELATIONS with relatives in case if they have hurt me by putting evil eye on my family members… I hope sheikh you will get my point… Its the matter of honor