There is a phrase which can be used to describe someone who is looking after someone but has sinister motives they want them to get unwell or more unwell than they already are, because they want attention from other people at the expense of their ward.
Example:
It's terrible what they found out about Jack, a typical example of ......... can you believe he wanted Sally to get more ill all the while he was meant to be looking after her?
I'm certain it exists, I just can't quite place it.