You don't mention where he lives. If he is living alone, you already
know that is no longer safe - he needs supervision and support 24/7
and plans should be in motion to either have someone go live with him,
move him in with family, or get him a spot in an assisted living
facility of some type. You may not be ready for the concept, but if
smoking is permitted at all, he must be monitored while he's doing it
- all the burn marks you are seeing are bullets dodged, so if he sets
the house on fire, or himself, you can't say later you weren't warned
there was an issue.

If he is living with family, some AD sufferers will quit if matches,
ashtrays and cigarettes are removed - just due to being out of sight,
the person may forget the desire to smoke.

You can designate a smoking area and not allow cigarettes, lighters,
matches etc. to be kept anywhere but in the designated spot (or better
yet, have someone in the family be the keeper of the smoking materials
such that dad can't get them without asking the family member to dole
them out). I do think the very real risk of fire makes it worthwhile
to be completely strict about this. You can then make the designated
smoking spot as safe as possible (i.e. make it fairly bare to reduce
fire hazard, such as no carpetting, and substitute plain wooden or
metal chairs for anything upholstered).

MIL was not a smoker, but her sister Norah (who also died of AD) was.
She quite smoking in the assisted living facility unintentionally.
They kept cigarettes and lighters etc. under lock and key at the
nurses station, and residents could go get them if they wanted to
smoke in the designated smoking room. Norah could never remember she
could get them when she wanted them, much less where they were, who
she had to speak to, or where the smoking room was. In short order,
despite a lifetime of smoking, she just stopped - and to tell you the
truth, if she felt withdrawal, she made no mention of it. Its like she
forgot she was ever a smoker - the habit vanished when the visual cues
were gone, plus being in a new environment without the old
associations.

M

<snip>

Chantix works by binding the nicotine receptors in the brain so the only
thing a smoker has to break is the habit.  And I mean really binding, as
in blocking, according to both the literature and my own experience.  
Welbutrin didn't do nearly as well for me - any time something went
wrong with my life (and with a parent with Alzheimer's, there's a LOT to
go wrong!) I was back on the weeds.  I've done one hell of a lot better
on the Chantix.

Also, with the Chantix, you can wean him off.  He can still smoke when
he starts the stuff - which means you can have fewer and fewer
cigarettes in the house as the treatment progresses and then none at
all.  By that time, he shouldn't even think about cigarettes (except,
perhaps, when in the presence of another smoker...).

Blessed be,
Baird