That is a very optimistic video...
Sure the FSF can try to reverse-engineer some firmware, but this isn't going to make a "Libre Phone", nor is further depending on Android, like they seem to plan, a good idea.
There are projects like PostmarketOS that are more serious about this and maybe the FSF will realize that they are better off collaborating with PmOS, but this tone-deaf and seemingly quite ignorant announcement of theirs doesn't make me very optimistic.