He may not actually turn up. This will lead Vishaka to switch panic button.
Shastri won't allow her to live in VR. She can't go back to Mumbai. So what's the best place to hide or rather who can take care of better than "Radhika"?
Now Dev has assumed the responsibility of Radhiaka's health, Vishaka won't stand a chance to argue that she will look after Radhika.
I think she will request Radhika to take her along with her. Vaishali and Amma will obviously support this request. This will be a parallel to Radhika entered PB earlier as SIL rather than DIL. Now the roles will be reversed.
And also this will give a closure to these statements.
Vishaka - "Your poti will go in Doli to Dehi"
Amma - " You will fold your hand and request me for Vishaka to come back"
Vaishali will be happy to receive Rad & Vishaka. And everybody will continue their dance after reaching PB.