Hmmm, I have some thoughts but they will be very random, so forgive me in advance ji.
From Radha's perspective:
I think her being agitated about Suhana trying to find out the reasons is alright. The kids of the house do not know that she was raped by a guy her husband sold her to. She is a rape victim and it is close to impossible at times to come out of that wound. Pschologically, this abuse stays with a woman-no matter how understanding a family may be. She finds a medium to exercise her frustration/hurt/anger/pain on something. Radha's medium is Deepika; moreso b/c he is her son with a resemblence to her rapist. That is torture for a woman. One needs to understand that the pain of rape exceeds rather than decrease for many.
Radha may be afraid of what will happen when the kids will find out. The love and respect will still be there, but she may be afraid that sympathy will also follow. For a rape victim (for my encounters with some) is that you need to be very careful in the emotions you emote towards them. Psychologically, every emotion weighs much for them. She may feel ashamed that the kids know, and will go into thinking they think of her differently (when that will not be the case, but the victim will think so). What will her Ishaan think now or the pity that the kids will have on her. Pity can kill, and for a victim is a major trigger for depression.
Suhana:
She is not wrong at all. She does not know, and feels that Deepak is treated unfairly. She has just begun to see what family means and the importance. From there she is being family to Deepak and rightly asks why that love is not given to Deepak. In her point of view, she is doing something she does not find wrong (and for me it is very sweet of her to take care of a family member like that). Suhana wants to know, and in a joint family I think she deserves to know-at least something. If no one is going to tell her anything, then she has every right to talk to Deepak and give him affection of a family.
It is very difficult to actually take sides for me. Solely going by half a heart, I would love to take Suhana's side b/c I feel bad for Deepak. As an outsider I see no fault of his, and see his mother treating him unjustly. I see Radha's ordering the family to stay away very bad. However, with the other half of my heart and mind I see Radha, a victim of something I cannot psychologically feel but have seen. The horror rape leaves behind can be something no other abuse may inflict. The fear of losing dear ones to that abuse, the pity, the self-hatred-it is unimaginable. It is very difficult for a victim to share something so painful. Radha's reactions are not wrong or mean in that sense b/c this is how she may cope. No matter how wrong I may see it from one view, the other view shows me a woman in pain.
That's all for now. Running a bit late ji. Sorry if not making sense.