The Joyetech/Ovale eRoll/Mini is an awesome tank (not cartomizer) based cigalike - he can use any juice he likes with it.
Here are my cig-a-like starter kit suggestions:
Halo G6: Electronic Smokeless Cigarettes G6 | Halo Cigs
V2: Electronic Cigarette Kits | Standard Kit | V2 Cigs
The WTA and variable voltage are not negotiable for me -- I'd be right back to analogs.
Okay, so here is what I think. I believe your dad has smoked so long that the feel of a cigarette in his fingers, or dangling from his lips, is as much a part of the problem as the actual act of smoking it. To get him over that part of the habit, essentially to brainwash him and sell him on vaping, he HAS to initially have something that is as close to a real cigarette as possible. It may last him years, or it may only last him a couple of days, either way, this must be the starting point.
I agree completely with one of the 2 cigalike kits suggested above, to give him the physical feel of a real cigarette. Personally, I think the eRoll is going to come the closest as far as size/weight, as the G6 is SUBSTANTIALLY heavier and longer (but will provide much longer battery life and still somewhat feel like a smoke). I would try the eRoll first.
The Whole Tobacco Alkaloid, or WTA ejuice is going to be the other essential part of the equation for the smoking effect. WTAs have small amounts of other tobacco alkaloids in them that affect the body as well when vaping. They help "mimic" the effect of tobacco on the body. Standard ejuice ONLY contains nicotine and is NOT ENOUGH for some heavy smokers. They NEED the other alkaloids (ask me how I know).
The eRoll for size and feel, and the WTA for effect, will be just about as close to a real cigarette as you can get with what is on the market today.
The caveat: Think of this hardware as a transitional/disposable setup and investment. This is money you have to be willing to throw away, up front. It is ONLY meant to get him into the vaping mindset. Once he is fully committed to vaping and not smoking, you will be shopping for better equipment that will support longer vaping time between refills and charges.
As always ... YMMV!
HTH