Sapna Babul Ka Bidaai, reveals the secret

Alekh in Bidaai on Star Plus has always be shown to be in great turmoil. When he was much younger, he had witnessed the death of his grand-father, and that incident had badly shaken him, to the extent that anybody would have mistaken him for a mad man. So, when Sadhana marries him, she spends her time and effort trying to make him better, and a lot of her efforts seem to be succeeding. She does this inspite of the best efforts of her mother-in-law who does not trust anybody else in the case of Alekh, and slowly starts to discover that somebody is deliberately doing actions that seems to worsen Alekh's problems.
Ranbir also starts showing strange behavior, as if he no longer cares for people, and for his brother, but after a confrontation with Sadhana, he reveals that he is doing all this as part of a drama so that he can find out who is trying to scare Alekh, and wreck his life. Together, they try to make Alekh face events of the past so that they can find out who is the one who is doing this. The other family members really don't like this or appreciate it.
And then the episode happens where Alekh remembers all that happens, and surprisingly, accuses Ambika of being behind all this, and also of having killed his grand-father. Ambika finally accepts that she has done all this, and it is her envy of Vasu that caused her to do all this.