He later returned to the hospital after his symptoms worsened, and he was put in isolation there on September 28. He had been receiving an experimental treatment, brincidofovir, a drug that had previously only been used to fight other viruses. There are no more remaining doses of ZMapp, the experimental drug used to treat Kent Brantly, the American doctor who was previously diagnosed with Ebola and treated in Georgia.

The fact that Duncan was turned away when he first attempted to seek treatment will likely become a point of further controversy. Between the two hospital admissions, Duncan writhed on a bed in a Dallas apartment, and he came into contact with up to 50 people, including five school-aged children. Health workers are currently monitoring the exposed individuals for signs of the disease.

Wow, Ebola killed him frighteningly fast.

Why did he come back to Texas? Trying to get more medicine / antidote?

He wasn't sick when he left Africa.  He came to Texas to see his family.