There are so many reasons why the information is true.
1. It would be incredibly difficult to fabricate this chain of information. There are other people involved so the emails can and will be cross checked. The information is real.
2. There is nothing about the disclosed information that does not make sense. Hunter had these dealings and we know that Joe knew as did the Obama state department.
3. If Hunter himself didn't drop these off- he left a trail of enemies who could have. I would be interested to know what the last entry from these laptops was dated. If there are none later than 2017 on these- it could have been his ex wife who got dragged over the coals by Hunter and has to be sickened by the family corruption. It could have been somebody who was blackmailing him - a drug dealer. Perhaps the dealer got whacked.
But back to your post- if Hunter's lawyer called the computer guy and asked to get the laptops back, then Hunter dropped them off. Otherwise how would he know where they were?
We will eventually find out who dropped them off and Giuliani, like him or not understands that. He's an experienced and accomplished prosecutor.