It looks a bit spindly, like it's not getting enough light. It's one of the Birdsnest Anthuriums but if it does look like that because of low light it might be difficult to identify. A. hookeri is one of the common Birdsnest types but it doesn't normally have leaves as elongated as those. A. plowmanii is another one, the same story with the leaves. A. jenmannii and A. coriaceum are also birdsnest types. There are a lot of hybrid hookeri these days, although your mother's may predate a lot of the hybridisation work done on the species.

I'll ask her what window she has it in. She normally keeps in an east window if possible. I'll also ask her how much new growth it gets per year. It also may just need a new change of soil and a trimmed root ball. I just reread the texts she sent me about it, and it DOES still bloom, although they're lighter in color and more rounded. The leaves have always had that skinny, ovoloid shape, for as far back as I can remember.

I was looking at different varieties- might it be an a. cubense? Has similar stem/leaves.

As mentioned before, there are a number that are similar except for the
elongation of the petioles and leaf blades. A better way is if you can
get photos of the flowering of the plant and compare those rather than
leaves.