Answered by Mufti Eunus Ali
I want to ask if my step father touched me and kissed me with lust and desire my mother and step father nikah invalid or valid?
My step father has changed so much now he has beard and pray 5 time a day.I dont want to separate my mother and step father because he is changed so much he has beard and pray 5 time.If theres any solution please tell me
When a man and woman come into physical contact (amongst other actions) which is combined with lust from either side the ruling of al-Hurmat al-Musaharahwill take effect.
This means that the mother (and lineage going above) of that woman and her daughter/s (and lineage going down) will become eternally haram for that man and marriage between them will be impermissible.
Likewise the father (and lineage going above) of that man and his son/s (and lineage going down) will become eternally haram for that woman and marriage between them will be impermissible.As a result any existing relation between the above will also be terminated.
In regards to your question as the kissing and touching was combined with lust and desire the ruling of al-Hurmat al-Musaharah has taken effect and the marriage between your mother and step father has therefore been terminated.To avoid them living in sin they should be informed about this.
For a detailed explanation of the rules of al-Hurmat al-Musaharah please refer to the link below:
Only Allah knows best
Written by Mufti Eunus Ali
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Al Fatawa Al Hindiyyah, Volume 1, Page 302, Darul Kutubul Ilmiyyah