The CHL rules are different than NCAA, so short answer is no. There was a brief period during covid where players who would play in cancelled leagues like the OHL could play in the AHL, and if they had done so previously, they could continue in the AHL instead of going back to OHL once it was back up and running (ex. Jean-Luc Foudy, Jacob Perreault).
Typically though, CHL players are either in CHL or in NHL until they're 20 years old (by Dec 31 of that year). Otherwise they're not eligible for AHL/ECHL and must return to their junior teams. They can be signed by their team, but if they aren't playing at the NHL level, they must be loaned to their CHL team either way.
Dumais is 18 and turns 19 in April of next year. So he will either be in Q for 2023/24 season, or the NHL. Q is the much much more likely option as even though I like him quite a bit, he still needs to add strength and work on skating more than he already has. So anticipate 2 more years of QMJHL action for him and his first professional season in the AHL in 2024/25