Lets see: One Million bucks minus 15 years of medical care leaves not much of anything. I see no financial incentive here.
The "medical care" that Terri has received in the last 10 years has consisted of sticking her in a dark room with the blinds shut, lying in a hospital bed in a hospice which he is NOT PAYING FOR (compliments of his pro-death lawyer Felos and in violation of FLORIDA STATE LAW, you know, that law that you consider so precious, that one?), putting a bolus of food daily through her feeding tube (inserted not for Terri's benefit but for the ease of the caretakers), and, if she's lucky, turning her to prevent bedsores. Those costs are minimal.
The more expensive rehabilitative and therapeutic costs occurred BEFORE the malpractice settlement. Once the settlement was final those were abruptly ended, a DNR order was issued, and Michael requested several times Terri not be treated for common medical problems that occur during prolonged hospitilization.
The size of the award was specifically tied to Terri's projected lifespan, which, according to her husband under oath was to be "normal".
The fact of the matter is the money has NOT been spent on her care, but on Michael's attorney, so your estimation of the cost of her care is moot.