(CNN) -- The drug is finally in Josh Hardy's system, but his father says his ailing son is still looking at a very tough road.
Josh's parents got what they'd been praying for this week: a chance to get medicine that could help their 7-year-old son survive.
The Chimerix pharmaceutical company said Tuesday that Josh would receive medicine that doctors hope will help him. He got his first dose of the drug, brincidofovir, on Wednesday.
The company had previously denied calls from the family to give him the drug, arguing that spending the time to help Josh and others like him would slow efforts to get the drug on the market.
The boy's story drew national attention as his parents and supporters pushed the company to change its mind, through online and media campaigns.
"Josh has a long road to recovery," Todd Hardy, Josh's father, told CNN in an e-mail Thursday.
He said his son has stopped getting worse -- that he was deteriorating last week and now he's not. Josh is expected to take the drug for at least 12 weeks.
He still isn't taking any food or drink by mouth, and his 5-year-old brother, Jude, "is purposely torturing him by drinking carton after carton of chocolate milk that's available in the ICU break room," Hardy said.
Josh's journey began when he was diagnosed with a rare form of kidney cancer at 9 months old. Over the years, cancer turned up in his thymus, lung and bone marrow, and each time Josh beat it.
But a bone marrow transplant left Josh without much of an immune system, and in February doctors diagnosed him with an adenovirus that spread through his body.
Now he's in critical condition in a Memphis, Tennessee, intensive care unit as the virus ravages his body. Josh is in heart and kidney failure.
A Facebook page dedicated to the online campaign to help Josh get the medicine posted a photograph of the boy, along with the message: "Please pray that the drug is as effective in combating this virus as we hope."
CNN's Dana Ford and Catherine E. Shoichet contributed to this report.