I thought that Lakhu loved his brother but it looks like for something as small as Ramu being suspicious of him (and with good reason) it was enough for him to want to get even with him too. In fact he wants to this to happen (find out that Sudha is alive) so he can take his place because then he will be able to disgrace his brother in front of everyone. And Bhabi seems good with this idea as well, in fact she is the one that mentioned it. Also, it doesn't seem she was upset with the fact that Lakhu did what he did (switch letter to have Miu killed) but the fact that it would ruin her plans for extracting revenge on Miu, Sudha and Ramu!
What kind of family are they???? How can they blame an innocent child to the extent they don't even care if she dies? Even if Bhabi is misguided (blaming Miu wrongly) this does not show a good character that she is willing to blame a child (who is not capable of making sound decisions like she should be able to as an adult) and doesn't care if she is murdered.
Wow, what a family!
BTW, think Mitil acted brilliantly again today.