A Sedge possibly.

Could you show us a photo of the plant(s) outside?

Here's the outside ones. . . the bulb section is not as visible underneath the soil.

It could actually be a rain lily-zephyranthes

I was thinking the same as trini 1

If an ornamental need to see the flowers.

"Grass type from Thailand?"
Does your neighbor use it for cooking? If so, possibly lemon grass?

I also think it is lemon grass.

Lemongrass have leaves that are thick, flat blades, doesn't look like those pictured.

I hope you can figure out what it is and take proper care of it...looks like it isn't thriving right now, imo.

@trini1 + @alisonoz - I think you're right!! Looks just like rain lily-zephyranthes on google images.

@jean001a - I've only owned them for about 1 month, I haven't seen any flowers, seeds, or dried buds. However, the ends are slightly crispy & I could see where it could've had stems on certain stems. Getting excited!

@regine - I have broken a stem or two by mistake and there isnt any lemony scent or flavor, but I thought so too & have done some extensive research & the lemongrass blades dont match well enough as Donna mentioned.

Picture of Rain Lilies from the net:

@trini1 + @alisonoz - I think you're right!! Looks just like rain lily-zephyranthes on google images.

@jean001a - I've only owned them for about 1 month, I haven't seen any flowers, seeds, or dried buds. However, the ends are slightly crispy & I could see where it could've had stems on certain stems. Getting excited!

@regine - I have broken a stem or two by mistake and there isnt any lemony scent or flavor, but I thought so too & have done some extensive research & the lemongrass blades dont match well enough as Donna mentioned.

Picture of Rain Lilies from the net:

{{!gwi}}

photo of the bulbs for reference

I have updated the disease & pests thread, so they can help me identify the best care for the ailing plants. Thank you for all the input, additional suggestions are more than welcome.

yes, well they are definitely bulbs not a grass, and I think zephyranthes are your best bet.
They really are not "ailing" and I can't see any signs of disease. I think what you have inherited is a slightly pot-bound clump of bulbs that have multiplied over the years but been cramped. They won't thrive in that bottle of water, or survive too long really, in the ground or in a pot is best.
They have been planted deeply or perhaps have worked themselves down in the pot over time, so plant them either to the same level they were at, or at least 1/2 the depth of the brown part. All they will need is watering in and add some fertilizer to the soil and gradually bring them out into natural light.
They will flower better in sun, and flowering is sporadic and can be triggered by rain-storms - hence the name.
In my climate, sub-tropical, they do go dormant at times and can lose all their leaves, so I would not expect them to be leaf-perfect all year round.

@alisonoz. Okay, this helps a lot! I have half the bulbs inside in the jar w/ marbles & half outside in the pot, I should combine them to all outside.

When they go dormant, should I stop watering or continue the usual water schedule to dampen the soil whenever it dries out?