In social media posts, Nick Gordon said he's been prevented from visiting Brown, the daughter of music legend Whitney Houston.
"Let me in the hospital to see my girl and let her hear my voice," he tweeted Saturday. "If she hears my voice, let me massage her,
play her favorite music I believe it will help."
But Brown's father slammed the accusation, saying Gordon was offered a chance to visit her.
"Let me be very clear, Mr. Gordon was offered an opportunity to potentially visit Bobbi Kristina and he declined to meet the terms of any possible visit," R&B singer Bobby Brown said in a statement through his lawyers.
"Obviously Mr. Gordon is not as desperate to visit Bobbi Kristina as he wants the world to believe."
The statement did not specify what the terms were.
Without specifying the details of those terms, Gordon's lawyers said they advised him against meeting them, "particularly in light of Mr. Brown's inability to guarantee access."
"In an effort to do all he can to visit, Nick has repeatedly offered to meet with Mr. Brown privately to discuss his request in person, rather than through lawyers," lawyers Randall M. Kessler and Joe S. Habachy said in a statement. "Those offers have also been rejected. We hope Mr. Brown has a change of heart."
Bobby Brown's attorney responded with another statement, saying Gordon has yet to tell Brown in writing what happened to his daughter.
"Due to Mr. Gordon's failure to place in tangible form his understanding of the events that lead to the hospitalization of Bobbi Kristina, there is no reason for any additional discussion with him," attorney Christopher Brown said in a statement.
"Mr. Gordon has every right to remain silent and not share his version of the events with Bobby Brown. We are only concerned with individuals that can help Bobbi Kristina and bring resolution to this investigation."
Bobbi Kristina Brown, 21, remains in a medically induced coma at Emory University three weeks after she was found unresponsive in a bathtub.
Doctors are attempting to slowly lift her coma, according to sources close to the family. Her breathing tube has been removed, and she will now be ventilated through a hole in her throat.
Police have said they're treating her case as a criminal investigation after she was found on January 31 at her home in Roswell, Georgia.
The extent of her injuries is not known.
Her mother, who died in 2012, was similarly found in a bathtub. A coroner ruled Houston's death an accidental drowning, with heart disease and cocaine use listed as contributing factors.
Brown is her only child.