An aunt and uncle from New Zealand had flown to the hospital to be with Joshua's father Andy, mother Rachel and sister Ashley.
Waite used to live in Hamilton, Garrett said, but the family moved to Australia after the father found a job there.
"It's a very, very trying time and I wish I could be there with Joshua, but I've got to stay here to look after my grandchild," Garrett said.
"[Joshua] is not an Australian citizen, so he's not going to get any of the medical benefits that the Australians get."
His aunt Raiha Hooker has started a givealittle fundraising page to help Joshua's parents.
"I started this page to assist his mum and dad in getting to the hospital, toll fees, parking fees etc," Hooker wrote.
"The last thing I want them to have to think about each day is this cost.
"Money will be used to help Joshua with his rehabilitation when he gets better."
Garrett said the family was grateful for "every bit of help and support" they could get.
"All we want is for him to wake up from his sleep and to come home," Garrett added.
Kippa-Ring man Jake Ashley Law-Cobbo, 18, has been charged with grievous bodily harm and appeared in the Redcliffe Magistrates Court on Monday, the Redcliffe & Bayside Herald reported.
Law-Cobbo did not apply for bail and will be held in the Redcliffe watch-house until tomorrow, where there may be a bail application.
The defence has been ordered to provide a brief of evidence by June 26 by Magistrate Mark Bucknall.
The case will return to court for a committal mention in July 5.