Maranta problem
There can be a few reasons for this; this article will help you.
https://www.gardeningknowhow.com/houseplants/prayer-plant/brown-leaves-on-prayer-plants.htm
This plant and others were in a cold house for several days.
If they are only drooping, just provide their correct care and environment. If damage is evident, pruning may be needed to prevent rot.
This article will help you to care for them:
https://www.gardeningknowhow.com/houseplants/prayer-plant/maranta-prayer-plant-peacock-plant.htm
We bought this plant last weekend from Kew Gardensand have kept it in a tray where we add water. From yesterday my son started to notice a smell that was like sick. We identified that it is coming from this plant. The smell particularly comes from new rolled leaves. Is this normal?I have moved it 8nto the kitchen but I love this plant and want to be able to move it back
Some people may find the plant unappealing. You might trey having good smelling plants, nearby!
https://www.gardeningknowhow.com/houseplants/hpgen/aromatic-plants-indoors.htm