I think the blood donation will come when Raghav will be guilty of all the bad things he did for her...that would be in process of him falling in love...
& That would be time, where Pallu completly ignores him...he will try to please her in all ways..but she won't give any head to it..
About hospital scene, may be she is that doctor who operated Amma..I don't want any sickness track for Pallu.she already has lots of issues, & sickness on top will be too dramatic