But Danny Hauser and his parents credit their alternative therapies, not the chemotherapy, for the doctor's good news that 13-year-old's tumor has shrunk.
Danny, who has been diagnosed with Hodgkins lymphoma, will leave his family's farm in Sleepy Eye, Minn., today to undergo another round of chemo, treatment he insists he doesn't want.
"Because it's poison," he told "Good Morning America." "That's why."
His mother, Colleen Hauser, said the chemo treatments are hitting her son hard.
"There's a lot of crying," she said.
She and her husband are worried that the chemicals used to treat cancers like their son's will leave him with damaging side effects.
Colleen Hauser has maintained that she fled with Danny last month because they wanted to treat his cancer with natural remedies despite a judge's ruling ordering him to undergo what doctors said was life-saving chemo treatment.
She said it was the boy's decision to flee the family's Minnesota farm last month when a judge ordered him back into chemotherapy.
Hauser has not been charged with disappearing with her son, saying she had no choice but to go with him.
"Danny was going to run away, then what do I have?" Colleen Hauser said shortly after returning to Minnesota. "I mean he was going to run, and that just broke my heart. I can't have a kid, one of my children, run away from something they should face head on."
While the family is now obeying the court order to treat their son with chemotherapy knowing they will lose custody of Danny if they don't, the Hausers keep a mix of natural supplements and treatments in the house. That, they said, is what they believe is helping Danny.
"I think it appears he's responding to the chemotherapy, but I think he's responding greatly to the alternatives also," Tony Hauser said.
But the prosecutor involved in the case isn't buying the Hauser's claims that Danny's progress came from alternative therapies.
"That's not because of ionized water," Brown County attorney James Olson said. "That's because of chemotherapy."
Danny said he dreams about regaining his energy and his hair. And one other thing he's missed out on -- bear hunting.
Danny has said the chemotherapy gives him headaches and makes him dizzy, according to The Associated Press.
The Hauser family is Roman Catholic and believes in the do no harm philosophy of a Missouri-based religious group called the Nemenhah Band,which believes in natural healing.
Hauser said in previous interviews that Daniel's initial round of chemotherapy had horrifying and painful side effects.
"He literally couldn't drink," Colleen Hauser said. "You literally couldn't even see his teeth; it was engulfed in his gums. "
The Hausers were the subject of a nationwide search by FBI and other authorities for over a week before Colleen agreed to go home with her son.
The case became an international manhunt with Interpol being notified and U.S. Marshals being deployed to Mexico from the San Diego Field Office and the U.S. Embassy in Mexico.
According to one source, the marshals and Mexican law enforcement officers were in Tijuana looking for Hauser and her son before their return to Minnesota.
Hauser's husband, Anthony Hauser, who went on television, pleading for them to return home, said that he believes his wife saw X-rays of Daniel that scared her.
"I know you're scared and I feel that you left out of fear, maybe without thinking it all the way through," Hauser said.
Authorities had promised Colleen Hauser in a May 21 press conference that they would not take law enforcement action if she showed "a good faith effort" to come back.
Daniel's court-appointed attorney, Phil Elbert, said Daniel has seen the most recent X-rays of his tumor, which show that the tumor is a white, see-through mass. Previous X-rays had shown a dense, black mass, according to the AP.
Elbert said Daniel will continue chemotherapy if he has to, even though he doesn't want to.
In an affidavit, Colleen Hauser said she seeks the court's forgiveness for fleeing with her son and thanks the judge for allowing Daniel to stay with the family after the two returned from California.
"It is so important to Danny that he be surrounded by his family," the affidavit read.
The Associated Press contributed to this report.