Clear answer: Yes, he should be if he's the one who has the most insight about your users. (He actually should be that guy, but you never know...) Like every interaction, watching a video as a user creates an experience.
At my work, we have some people started to make videos about our SaaS out of nowhere. I didn't even know about it. When I watch the videos now it's sometimes a real pita. Despite the lack of craftsmanship in video/audio, the content is sometimes completely useless ("click here to do this... click here to do that..." instead of "if you do this, our product will also do that and you don't even have to bother! yay!").
Your UX professional need to overview especially the content of the video. Does it explain your fundraising properly by addressing the users expectations? Especially in this case: Does it address their fears about giving away their money? Will it be in reliable hands? Too much "shiny super awesome promo style" might be the wrong way to go, instead you probably need to go for a "not so exciting, but solid and trustworthy" strategy. But this only your UX pro can (or should be able to) answer.
He also should brief the video guys about the creative strategy but leave the details to them as they (hopefully) know what they do. When it comes to approve the final cut, please don't let your very own oppinion judge. Instead ask yourself "have all the essential issues, our users have, been addressed in a way they understand?" If the answer is "yes" then the video is ok. "I don't approve the vid because I don't like the blue tone" or "I don't approve because xyz is not mentioned enough" is the best way to ruin a video project. (Says someone who used to work on vid projects for several years in a professional environment and even broadcast)