I’m sorry that this is all happening to you! You are very young to be dealing with all of this. Where does your dad live? Can you go visit him? Perhaps the best way to stay in touch is to write him letters and include your photo. You can also call, or maybe you can talk via Skype or another service where he can see you. Sometimes phone calls confuse people with dementia as their dementia progresses.
His dementia will always get worse, even if you guys do your best to help him. That isn’t your fault, it’s just the nature of the disease.