Today Birju confirmed our doubts that he believed what Radhika was saying. I think the reasons why he believe Radhika is not only b'coz he loves and believes Radhika a lot, but also b'coz he knows the nature of both the sisters in and out. In fact he himself is the witness to many of Visakha's runaway expeditions like the ones :
1) Birju knows that Visakha ran away b4 the RP puja, although he does not know that indeed it was Radhika itself wo did that puja and Visakha appeared in the morning.
2) He himself has witnesses Visakha's Mumbai runaway expeditions and Radhika's sacrifice to stop her from doing that.
3) He has again seen Visakha running away from the store room of PB, b4 RaDev's Goa HM trip.
4) He has witnessed Visakha running from her second marriage
5) Also he has seen how unworthy is Visakha of all the help Radhika has done for her, how ungrateful she feels to both RADev who has done so much to hide her mistakes from the family. He has seen how she transfers all her mistakes on Radhika's shoulders.
Its a good sign, as I think Devki would back stab Radhika, which she would not expect at this time and then it will be Radhika who would remember that photograph with as usual Visakha hearing and following Radhika, Birju to get hold of that photo and destroy it.