In this case, it is likely that they wanted to use his voice if the videos done in collaboration went particularly well. So the fact that it’s hus voice has a specific reason to be. This could hold as a claim, I think.
That might be a valid claim. But I would find it to be a very weak one unless they can come up with evidence that their use actually pretended to be him. The strongest argument here in my opinion would be that they hoped people would assume it’s him, even though they never state it. In the end it would be a very fact-reliant case, and subjectively I wouldn’t be convinced of an attempt to mislead based just on the use of a voice alone.