The brotherhood thingy I was talking about was only between the three brothers, I am not too fond of Tian Qi, cause I think he is such a wimp.
Yubo's ultimate goal was to save the people of Shui Yue Dong Tian, he didn't deliberately hurt Doudou and Tong Zhan, he only did that because he had no choice. And Tong Zhan did not hate him even though he apparently 'snatched' away Tian Xue, which goes to show how much he respect Tong Bo as an older brother.

The bond between the brothers runs deep and strong, which is one of the best things I like about the show.
As for the leaving Dou dou in the rain, yeah, he was being quite a creep, but what else should he do then? Tian Xue was (if I remember correctly) his wife at that point of time, or at least about to become his wife, and she was sick and calling out to him. Of course he had to go and attend to her! Besides, he still had to put up the act that he didn't care for Doudou.