As I said what they are using is Project. They use it for estimation. They use it for task tracking.
Any lack in the tool doesn't alter the fact that they are using it for that.
I have worked on projects with up to about 100 people and I haven't worked on single team projects for probably 15 years. And everyone uses Project. I have never heard any suggestion for any other tool. The only alternative that usually occurs is when no tool at all is used.