A Florida grandmother is facing a second-degree murder charge after admitting to killing her disabled grandson because she was concerned about who would care for him when she passed away, police said.

Joel Parks, 30, was found dead Sunday in his grandmother's apartment in Bradenton, north of Sarasota, Bradenton Police Department Capt. Brian Thiers said during a news conference on Tuesday night. Parks' sister discovered his body.

His grandmother, Lillian Parks, 87, made "spontaneous" and "concerning" remarks that she had purposefully overdosed the man "with the intent of taking his life," Thiers said. It was not immediately known what drug was used.

She told police she "was worried about who would be caring for him in the event that she passed away."

Thiers said Joel, who was "unable to care for himself," stayed in a home during the week and with Lillian on the weekends. His father had died and he was estranged from his mother.

Parks is being treated and evaluated in protective medical custody, and when she is released, she will be arrested, police said in a statement Wednesday.