Q.citronella plant
Can I share my citronella plant with my mother-in-law and others? If so, please tell how to go about separating the plant. Also, can it be potted in about 1 ft deep and maybe 18 inch wide container? Would it be good to add river rock to bottom to ensure good drainage and use moisture control soil?

To make more Citronella plants, you can start new ones from cuttings.
You will need to start these in smaller pots.
The pot size you mention, would be for a more full size plant.
Here is more information for you.
https://www.gardeningknowhow.com/edible/herbs/scented-geranium/scented-geranium-
https://www.gardeningknowhow.com/ornamental/flowers/geranium/how-to-save-geraniums-over-the-winter.htm