My parents live in one of these facilities. It's a competitor to Longhorn. They have the same deal - initial $800k deposit, 90% refund, and a monthly rent. They really like it. A big concern, as mentioned above, is solvency/bankruptcy of the parent company. The facility is 5 star and the food is great. It's a lot like resort living. They do raise the "rent" every year by 1-2% for "inflation". Dad is paying the monthly rents through a military pension, university pension, and social security. So when he passes my mother will paying her part with true retirement savings. Dad's joke is that if he is on life support, don't unplug him because he's paying the bills as long as he is alive. At first I thought he was joking but I realize now he's right.
The $800k is nothing more than a security deposit in case the payer runs out of money for the monthly bill and they will take the rent from that.