Aayii Saheb is not the Tyaag ki Murti that she is made out to be.
She may not be Badi Hasti, but she is no Tyaag Murti either.
I am going to be ruthless in my observation of her:
Everything she does has a selfish motive. For her family = herself.
Why did she take in the son of the man who murdered her husband?
Because Dutta was the only male, next of kin.
She had daughters (where was the third? we saw only two; maybe on the way? when Shriram Patil was pushed down?)
So she needed a male in the family. There was Dutta. Same blood line. No adoption issues.
He would grow up and look after her and her daughters.
In a mean, male-dominated Patilwadi/Ratnagiri or wherever they were, it is hard to survive without a man in the house. In the place where you live, you command respect only when there is a man in the house.
Face it, it happens everywhere. Try getting a plumber or a mason, they will ask you if they can speak to "Saheb" in the house. They look confused when you tell them you (a woman) are the Saheb of the house.
So, I don't know if she let him study. I think, she just waited for him to grow up and take up a job and support them. I think her daughters were allowed to study (Remember Kala mouthing "mirror, mirror on the wall..."?)
She wanted her daughters to be settled first. So, she tried discouraging Dutta from getting married, telling him he needs to get a bigger house for the new wife.
Untill he became a don, she had no standing in the community. She graduated from being an Aayi to an Aayi Saheb.
She wanted a "Chaand Si Bahu", a beautiful bride for Dutta, a bride who would look up to her, besides being good looking and from a "cultured" family. Supriya was a good catch.
She saw her son staring at her at a friend's wedding, and Voila! She made the decision - unilaterally - that Supriya would be her Bahu.
She showed her power and influence (her huge Mansion, and Servants, Jewellery) to the would-be father-in-law, forcing him and is daughter to stay (quite contrary to really conservative Maratha/Patil conventions) in their house before their marriage.
She saw to it that they were impressed by the wealth and influence, and would simply not say NO.
We all know what happened to that story.
Then came Nakusha. AS took her in, only because she saved her son (her source of power, influence, wealth, security, whatever you want to call it).
And she loves to be magnanimous, and be loved by the community (all on the basis of what Dutta created).
She did not let them come for free; she employed them in the house. Note that it was a kind of Barter. They worked and were allowed to live there. So, it was not free.
She hated the thought of an ugly girl being her bahu. Untill that Pandit came and told her she was Dutta's protective cover. Then she accepted Nakku for the selfish reason: to be the shield for Dutta, not because she trusted her or had any affections for her.
AS's fears for her son are not out of deep maternal love. BUT her own sense of security and that of her family. That is why she has made Dutta extra special for herself. She is scared, like Nakku, Dutta will leave her.
To any normal person, it seems strange that she should have so much of attachment to Dutta, than to her own daughters. No wonder her own daughters resent her for it.
For the love that she showers on Dutta, she also exacts a price. His loyalty, complete obedience.
She is behaving the same way she did with Nakku after he forced her to marry him.
Aayi Saheb. You are unjust, selfish, just like the children you brought up. You know no gratitude, your faith is fickle.