Edwin Berndt and Edward Berndt, both 48, were arrested Monday after cops found the body of their mother, Sybil Berndt, still on the floor of their Houston home, covered in bugs.
Officers said they visited the home after a neighbor reported the woman hadn't been seen for months.
Edwin Berndt initially refused to let anyone in, but relented when cops demanded to talk to his mom.
Cops said the home was in "deplorable condition and smelled terribly." The woman's was found facedown, without underwear and a grubby nightgown pulled up under her arms.
The brothers told cops their mother had died after a fall and they decided to leave her there because they couldn't afford a burial or ambulance.
They claimed they were watching the NCAA college football championship game Jan. 10 when their mother "came in ranting and raving" and slipped fell on the floor.
She was conscious and talking for the three days before she died Jan. 13, the day after her 89th birthday, her sons told cops.
They admitted they didn't give her food or water before she died, police said.
During a search of the home, investigators found bank statements for accounts that totaled about $700,000.