Wa`alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear sister in Islam, thanks a lot for your question which reflects your care to have a clear view of the teachings of Islam. Allah commands Muslims to refer knowledgeable people to become well acquainted with the teachings of Islam in all aspects of life.
While asleep people are not in their senses. If a man utters talaq (divorce) while sleeping, it will have no religious validity.
In his response to your question, Sheikh `Abdul-Majeed Subh, a prominent Azhar scholar, states,
Divorcing the wife while sleeping has no religious validity. So if a person utters the words of divorce while sleeping, such divorce cannot be considered valid if it is sure that he uttered “divorce” while sleeping. The Prophet (peace and blessings be upon him) is reported to have said, “The pen has been raised for three persons [meaning they are not held accountable for what they do]: one who is sleeping until he wakens, a child until he reaches the age of puberty, and an insane person until he becomes sane.” (Ahmad, Abu Dawud, At-Tirmidhi, An-Nasa’i, Ibn Majah, and Al-Hakim)
So if the issue is as you said, that he was sleeping while uttering the word “divorce,” then those who have issued such verdict have mistaken and have given a wrong ruling. I think they are not specialist scholars in the Shari`ah. Bear into consideration that India has many reliable Muslim scholars and imams who are well known for their profound knowledge of the sciences of Shari`ah.
Allah Almighty knows best.