Raju is very much fit and they are showing it.
Yes he is faking his illness and we are shown it properly only observe it minutely. Thanks after Meenji's post (http://www.india-forums.com/forum_posts.asp?TID=3976239) even I try to understand and I feel he is only faking. I will not add her points you all can read it. But I want to say something else.
See after night episode when Raju got first attack of asthma he took the puff (which is empty according to me he is even acting to be asthma patient I guess.) and then misplaced it. The inhaler was dropped down to his leg actually and not to her bag. See carefully inhaler is near his leg and Madhu's bag is little away from inhaler and his leg.
After that scene changed AK went to talk to Madhu on background Raju was doing something. Then AK went away and Madhu started talking to PK. Please see in background Raju is touching her bag. And earlier he was shown touching her bag in front of Madhu so that audience and other do not doubt on him. But in everyone absence he kept inhaler in her bag. May be he guess it that Madhu is feeling pity on him and will try to run.
When Madhu came back one thing he saw is inhaler like Meenji mentioned in her post. Before than anyone he saw that right on inhaler than Madhu and went to it so that no one doubt on him.
Yes we are saying Raju is attached to Madhu so soon? Can we guess why no he is not attached to Madhu. He is making Madhu fall for him. Have you all observe change in Madhu after star scene Madhu said to Raju - Sambhalke girna mat. When Raju was saying her he said he got an attack because of Gudiyan. He enacted story in such a way that Madhu felt for him. Madhu went directly against AK and started fighting on him. Neither he is mental and nor he is asthma patient.
Everyone is thinking they are making Raju dance on his tune but instead of feeling bad to show Raju like this if we see it properly and minutely he is still returned as RK. He is making Madhu fall him again. He is making it dual showing sweet Raju winning everyone's heart and actually he is still RK as in Rajkumar.
He is again doing combination of
Thoda sa ishq milaya thoda sa junoon milaya and milke kya khuba bana
Madhubala Ek Ishq Ek Junoon.