I think it's very admirable that you'd use your (probably hard-saved) money and other resources on a vacation for your father.
That being said, I can't imagine that the Poly bungalows come anywhere close to the ones in Bora Bora - the benefits of the overwater bungalows in French Polynesia, and Bora Bora specifically, are being surrounded by that impossibly blue lagoon, watching marine life pass under your room (we had a glass bottom floor with a light so we could watch fish, small sharks, etc day and night), and being able to step right off of your private patio into the cleanest water imaginable. I LOVE WDW, but the water has never struck me as being very clean - hard to see whatever fish might be there - and you can't swim in it (I wouldn't want to even if it was permitted). Is the view from the new Poly bungalows any better than the view someone who hasn't paid $$$$$ can get (either by staying in another castle view room, standing on the beach, or dining at some place like Cali Grill)?
Lacking the previously mentioned perks of the *real* bungalows, what is the point of the Poly ones? Why spend a king's ransom on something that, as far as I can tell, only approximates the look of the real thing without providing any of the actual benefits - the real reasons overwater bungalows even exist?
No doubt, a trip to Bora Bora is expensive, and the overwater bungalows there are not cheap. But taking a week-long vacation to French Polynesia (including RT airfare!) and staying in the most expensive room type is still cheaper than staying in the Poly bungalows for a week (not including travel, park tix, etc) - and that's INSANE.
Everyone keeps talking about just go to the real thing... it would cost the same... Ummm no, for us at least it would not cost the same... the Poly would be way less exspensive.
Also for us it is not about replacing the real thing just 'because'... it is about substituting for the real thing because that is the only realistic option for our family... financially and physically. When I travel with my senior parents it is an entirely different travel situation than when I travel just with my husband and kids (13/19).
Reality: nonstop 3 hour plane ride from Massachusetts (BDL>>MCO) for under $300 RT per person vs a 36+ hour plane (total travel time) ride likely with multiple stops, for $1700 per person to Bora Bora
Reality: No out of pocket for room cost as I would be using DVC points (already paid for) vs out of pocket $1000+ per night for the real thing
So for the basics... for a family of 6 for 4 nights in Bora Bora + airfare (based on prices quoted already by PPs): $14,200... likely we would have to add a second room so $18,400.
For a family of 6 for 4 nights using DVC points in a 2 bedroom at the Poly + airfare = $1200
Not sure about your math... but even factoring my DVC dues, buying park tickets and food is not going to come close to $17,200
However...
My BIGGEST Reality: Handicapped senior citizen who (besides missing a foot) cannot walk more than 40 or 50 feet without needing to stop and sit due to COPD. With WDW I know we can get easily get to transportation... rent a
scooter/use a scooter... handicapped bathrooms.. accessible pools etc. Unless a pool has either steps or is zero entry... it is useless to my folks and might as well be a big fountain to stare at.
Handicapped seniors (at least mine) do not do well with walking on sand (last time was a fall that dislocated a hip)... nor climbing ladders in and out of that pristine blue water with all those pretty fishies in that over the water bungalow in Bora Bora.
Seeing as the major highlight of my Dad's life recently was the Christmas Story marathon on TV over the holiday... I think sitting at WDW watching TV would be OK.... or walking outside to sit and watch the scenery and/or fireworks... or even fish for mutant bass...
My Dad was very lucky in his younger days... and he (and I) traveled to many fantastic real places... but now he is at the end stages of his life. Of course he would prefer the real thing... just like he would prefer to be 47 again with all his parts functional. But reality dictates what is possible for his travels now...