This is one of those questions it's not really possible to answer without knowing a lot more about the person in general, (and even then you need to speak to medical professional, not internet randos). ED's come in many varieties so for example if someone's focus was on feeling full or the desire to purge, they may not have any trouble feeding someone else under their care. Conversely if they struggled with portion sizes or regular meals then yes, it could be very challenging for them to look after a child.