End stages of Dementia

A fellow caregiver asked...

My Dad has Dementia now for the last four years and is totally dependent on his carers is all activities of living. He is on Grade 4 food and has difficulty swallowing/coughing etc for some time now. He has been sleeping now for the last three days and I feel he is getting very near the final stages. I would really appreciate your professional opinion regarding this. Many thanks.