QLD Horse Lease - No agreement

My daughter was given a horse to look after about 5 years ago. She had her for 3 years when the owner asked for her back and we gave her back at his request. About 6 months had past and my daughter went out to see her, to see how she was going. RSPCA were there, looking at his other horses that were in poor condition. The horse my daughter had had, came straight to her and was in extremely poor condition. She had lost weight to the point her eyes were sunken in, all her bones were protruding, and she had sores all over her body. My daughter asked the owner if she could take her back, and he said yes. She has not heard from the owner for 2 years. The horse is now in pristine condition, and my daughter has now had her a total of 5 years. Now the owner is asking for address details, etc. My daughter is reluctant to pass these on in case he wants the horse back. Does she have any legal leg to stand on. There is no written agreement and never has been.