Kaka's weird behaviour was already discussed in another topic.
Reposting my take again in this thread.
Please find it in bold.
You have exactly echoed my confusion regarding Kaka and Bondita's relationship.
Even I couldn't make out what he exactly wants Anirudh to do regarding Bondita.
On one side he preaches about relationships aren't erasable like the lines of our palm.
He also had hit Anirudh's nerve when he questioned that how long would he be able to contain himself from meeting Bondita.
Yet on the other hand, he reminds Anirudh to not forget about the injustice meted out to Tulsipur by Krishnanagar.
Not sure what to make out of it.
Kaka himself seems to miss his (ex-) bahu, her tarks, her innocence, etc.
May be he just fears of some situation where Anirudh would trade off all his rationality and justice for Tulsipur for his love, Bondita.
He also mentioned that Anirudh's decision impacts the entire Tulsipur. So, if by any chance Anirudh and Bondita's relationship rekindles, it could once again create more riots between the 2 villages than the ruckus and loss already created.
But he's also not blind to Anirudh's feelings. Maybe he is just hoping for a miracle where Bondita would return their "dead" Anirudh back by entering his life again without having Tulsipur to pay for their relationship.
Further adding to the above points, Kaka at this point, just likes the chirpy Vyjayanti who has brought back life into the house.
Once he finds Anirudh's changing behaviour due to Vyjayanti, he may even play cupid to get him married to her without knowing that it's Bondita herself.
He would see Vyjayanti as the replacement for the void left by Bondita in Anirudh's life. To him, getting Vyjayanti and Anirudh hooked up means making him strong enough to resist Bondita if they were to meet face to face some day.
And Tulsipur need not face any consequences of riots as such.