This free channel uses copyrighted material (items with a status of “Can’t monetize”) and agrees that all revenues from ads will go to the copyright owners. Every new video is tested before it is published to make sure that it meets the requirement.
However, when a published video's status gets changed from “Can’t monetize” to “Can’t see or monetize”, YouTube blocks it without any warning to the channel owner. Then, if three such blocks occur within a specific time frame, the channel may get shut down, which will take away all the other videos in the channel.
If a way is found to prevent the shutdown, it will be implemented here. Meanwhile, it is not clear how a downloaded video will be affected when the corresponding online video gets blocked. Perhaps the best plan is just to enjoy the videos while they are there.