Dev is a good person by heart. But he is weak. If to fight for love means to get drunk or try commit suicide to show what's your state of mind is, then I am sorry but that is not redemption. Its weakness. Since he is a mamma's boy, he cannot speak to his mother or stand for his love or Sona, he goes for easy ways (like his mother) and get drunk or stalk or suicide. Seriously. I fail to understand the beauty of these acts and how it justifies he is in love with Sona. Lets say he gets married in this state with Sona. Would he ever stand for Sona after that, I don't think so. In fact it will be a cage for Sona, from which she will find hard to run. Atleast now she has a choice (could be in a hurry or may be her mistake which can only be proved in future).
What he needs to do is not act all goody goody (sleep in her lap, eat happily her food) and lie to his mother which he always do and just plain speak to his mother. Oh boy am I expecting too much from Dev