Possibly. We haven’t looked into it or tried booking flights since pre-Covid. We had everything planned to go in April this year but that obviously never happened. If that’s the case he either goes to a consulate here or waits for his Canadian Passport.
From what I can see he will most likely be getting his DR passport renewed in Canada before goes to the DR if the DR requires it.
If he is a dual citizen, those citizens are normally required to enter the country using the passport of that country in which they are also a citizen.
Since he is a dual Canadian/DR citizen, he probably has to enter the DR on a DR passport, but that is up to the laws of the DR.
But you and I know that immigration laws in the DR are not always adhered to, or it may just be fine for him to use a Canadian passport. That is something to look into.