I know we are all dreading this turn of events. CV's are famous for butchering characters (they all need to be put into the cold storage)
Here I am being positive that Rohan is not turning grey, he's going to be as fair as ever.
But it's Sunday,
so let's enjoy our Funday by finding reasons (fact or fiction) for Rohan greying.
Please add your views ... the more absurd the better.
My reasons:
1. HOOK or CROOK 
1. Ashu-Rohan conversation- Ashu said by hook or crook, take care of Nidhi. Be there for her.
So Rohan decides he will be the crook and try to hook Nidhi by falling in love with her.
He will do it so that she runs in to the crook of Ashu's arm and then AhNi hook up for life.
2. STRANGER-DANGER

Rohan's observation when Ashu drops Nidhi after surgery- AshNi becoming comfortable with their stranger status. He decides to shock Nidhi out of her comfort zone. Otherwise poor Rohan will be driving her around for the rest of his life.
3. RUN RATE 
From past records, we know Nidhi has an excellent track record for running away from situations. (Mumbai, Kerala)
So Rohan will try to scare her, intimidate her and maybe even have Baba and DB turning against him.
4. NEVER SAY DYE

Maybe production house invested in hair-dye products and after the exit of old Ashu, they have surplus of it. New Ashu is comfortable with his grey beard, so who better than Rohan to experiment with - turn him grey and then paint him black.
5. FOOL"S PARADISE
Hopefully it's all to do with April 1st.