The AntsCanada Ant Forum's

is this okay or no? or it is bad if then what I need to do

If it is truly a dracula ant, the pupa should be fine. After all, this happens in the wild too, and that species is not extinct.

is the ant eating the entire pupae because if it is then there is a problem. If this has happened this is most likely because of stress

I am still baffled that this does not directly effect the pupae. The fact that ripping open the pupae does not cause the not fully developed ants to dry up is amazing and mind boggling. I guess logically the ants know what ones are close enough to maturity making it safe to drink their blood but still. Feeding off of the larvae makes sense because the pupae state should remove any scar tissue if I am not mistaken.
But the evolutionary advancement to be able to pull this off with out compromising the ants exoskeleton is a triumph in its self. Got to love the mini and micro world's.

To give you a little info, there are videos about Dracula Ants on the AntsCanada Channel. So just go and check it out and have a look. He explains a bit about them and it is quite interesting that they drink from their larvae and puppae and such but I guess they also eat soft insects or insect meat.

Perhaps even your own blood if you want to try a blood drop. ;P