Harry was left battered and bruised after being assaulted during a night out celebrating his sister's 29th birthday in January.
He suffered a broken nose and other facial injuries after two thugs had asked him for directions and he replied using sign language.
Writing on her Twitter account earlier today, Josie said: "Thank you to everyone who retweeted a raised awareness of the attack. Your bloody amazing. I owe you a lot of drinks lol!![sic]"
She also later retweeted one of her fans who wrote: "Glad they're treating it as #hatecrime too. Far too many people think it's ok to attack people because they are "different! x!"
Following the attack a distraught Josie later tweeted a picture of Harry covered in blood.
"I'm going to hunt the bullies who did this!The nicest guy ever was beaten up because they thought he was deaf & dumb," she wrote.
Disability campaigners condemned the attack and said the government's welfare reforms are to blame.
Philip Connolly, from Disability Rights UK, said the "shocking" attack was a reminder of the rising tide of hate against people with disabilities.
Josie's brother Harry became deaf as a result of suffering meningitis as a baby.
Avon and Somerset Police said: "We have arrested a 24-year-old man in connection with an assault at the Dojo Lounge nightclub in Bristol in January.
"A 27-year-old man from Cheshire was assaulted at the Park Row nightclub in Clifton in the early hours of Sunday 26 January, while out with family and friends. He suffered a suspected broken nose.
"The assault is being treated as a hate crime."
"A 24-year-old man has now been arrested on suspicion of causing actual bodily harm. He has been interviewed and released on bail until 30 May to allow for further enquiries to take place."
"We are still appealing for witnesses to the incident to come forward, as well as anyone who has information which could help our ongoing inquiry."