When your own parent disown you, do you still need their permission to go forth?

[Nipaka]

this thread will be useful

Permission for ordination

No, the rule applies to adults as well; unless one’s parents have died. Originally posted by Venerable Dhammanando on Dhammawheel: The Vinaya Piṭaka’s Mahāvagga states: na, bhikkhave, ananuññāto mātāpitūhi putto pabbājetabbo. Yo pabbājeyya, āpatti dukkaṭassa. “Monks, a son must not be given the going forth without permission from his mother and father. Should one do so, it is an offence of wrong-doing.” — Vin. i. 83 The Atthakathā comments: sace dve atthi, dvepi āpucchitabbā. “If both ex…

In brief - if parents already died no permission is needed. If a parent left you is also not needed.