I'm currently in medical school and you might be amazed at how often Wiki is used as a source to justify an answer.
and in worst case, damage your heart or lungs.
Worst case is death, typically due to a massive clot lodging in your lungs (also called a saddle embolus)
Really bad case is with certain heart conditions they can bypass the lungs and cause a stroke.
Just plain damage? That's probably "bad case."
A meningioma is a tumor of the brain covering, so it isn't in the brain tissue itself (although can press on it giving you significant problems).
In medicine we don't have a formal definition of "brain tumor." Instead we divide them into CNS (Central nervous system) tumors and PNS (peripheral nervous system) tumors. It sounds like they looked at the most common CNS tumors in adults. Gliomas is a large category that includes astrocytomas, oligodendroglimoas, and ependymomas. Meningiomas are tumors of the covering around the brain.
It doesn't mention neuroal tumors, which are tumors from actual neurons. Some people (like the parent) seem to think those are real "brain tumors" while all the other glial tumors in your brain are something else. I DEFY you try and convince a patient with a glioblastoma multiforme (a really nasty form of astrocytoma) that the mass in his head is likely to kill him within the next 12 months, but it isn't a "brain tumor."
When it is not necessary to make a decision, it is necessary not to make a decision.