IMO, this convo b/w grandma & grandson can be only 1 of 2 things - will or MG. Will ka ho sakta hai, coz even Armaan knows that if they're named the sole beneficiary, pariwar ka pyar will become non existent for Abhira (jo already hai, but it will get worse) & they cannot stay even in OH, so it will affect their relationship, so him wanting to tell makes sense.
Else I also like the theory about the whole truth of how her mom was thrown out & reason for ilzam and basically stuff that will alienate Abhira from MG - that also will have a similar effect on their relationship if Abhira finds out that Armaan knew & didn't tell her
I honestly cannot think of any other plausible reason, so I am expecting that Bhavna will do that shubh kaam for me
..Kya KP knows she is pregnant as the doctor is same who came sangeet day.
1