How to handle fathers dementi

I'm 23 yrs. old, father 70 yrs. old has dementia and I feel unprepared. He had some bad hallucinations and now he starts towards the stage where he begins thinking you plot against him. Mix all this with drinking issues...sigh. I have some anxiety issues myself and starting to get paranoid about him, keep wondering what's going through his head, what he could be capable of...Weird thing is that he isn't yet at the stage where he can't remember dates or can't tell time, well not all the way there anyways. Since I'm here on this site might as well whine a bit. I feel cheated, I shouldn't go through this at my age, you see, my parents had me pretty late. Also sometimes when I see him drunk I feel like I want to grab him by his head, shake him very hard and ask him what the f**k is wrong with you!! I know, I know, it's the disease, but part of it it's also him as who he was. I'll have to get me some help, a shrink, before I dive in myself in this mess. I'll keep reading on this site for experiences, advice. For what it's worth it feels good to dump some of the load. With friends or relatives it seems to me that it's kind of overwhelming for them to deal with such issues.