Husband insisted on leaving hospital after surgery

@blisst You don't say what stage of dementia your husband is in, but it sounds like you need to seek a durable medical power of attorney so you can manage his care. You can initiate this with his primary doctor.
This could be tough if he is still somewhat competent, and refuses to cooperate. Have you seen an attorney since his diagnosis to get all of your legal paperwork in order? It is best to do it before an emergency arises, and if possible with his cooperation, than to have to get the court involved later.

@sueinmn sorry, I believe he is stage 3 or early stage is what the doctor said. We do have all our legal paper work in order.

The standard of care in most hospitals/surgery centers is that when a patient is discharged, he/she must receive the appropriate discharge/aftercare instructions. Usually the patient or responsible person is asked to sign that they were received. If you do not get this information at the time of discharge, I would ask to speak to the discharge planning nurse. Or you can call the surgeon's office and explain that as his caregiver you need aftercare instructions including when the patient is to return for the post-op visit. Just remember, the squeaky wheel gets the grease. Sometimes we have to advocate on the patients behalf, especially if there is any question of the patient being able to understand and carry out the instructions. This is our situation as my husband has moderate dementia and would have trouble reading, understanding and remembering instructions.