To add to the comment above, instead of abusing the ER and costing more money, call his Primary PCP if he is still acting this way now. He/She should have a copy of his ER note anyway or get one. Explain what is going on and your father's symptoms should make him a priority for the PCP.
Sometimes it takes time to be referred to a specialist (Neurologist), but in the meantime, tests can be done. Your father could have a head injury and needs further evaluation by a medical professional. Let us know how things go.
It would be best to go back, explain to them what happened and they could determine if further follow up tests are needed and what they find.
Also ask them for a referral to an outpatient neurologist, once they address this concern, who can follow up with this on a regular basis.