Munshi must have told Anirudh's father everything that happened till that buddha died. Anirudh went for Munshi's son's wedding so Munshi will be blamed for it all the rich in dramas tend to do so. So to save himself he will tell everything.
The father does not accept nor did he expect Anirudh's move. So he does not consider the marriage and in his eyes Bondita is the buddha's widow and that is the easiest way for him to get rid of her.
Anirudh went in shock and was unconscious or was it a scheme against him don't know. Of course he will be the one to save Bondita.
The Britishers did not interfere with the religious matters. Sati, child marriage, Vidhwa ashrams they did not interfere.
Those days even now some women do not take their husband's name. But she called him Pati Babu cause she does not know his name as of now.