Can't get your senior to lie down and stay down? Try this:
A drop or two of Lavender oil on a cloth, then flip the pillow so it's against the mattress not next to their head. Every time they turn over, a new puff of lavender comes up to soothe. You want it on a cloth that can be laundered and refreshed with new oil, not on the pillow proper which will make it greasy. An old kerchief is fine.
Oils can be pricey and lavender buds from potpourri can work just as well except they also 'crunch' when crushed. You want them to sleep, right? But go ahead and experiment, even with yourself. An elder with hearing loss is less likely to be disturbed by crunching dried flowers/herbs/woods or even bath salts.
Your senior doesn't like lavender? Try eucalyptus, bergamot, sandalwood, rosemary, pine which seem to be universally perceived the same. Some like flowers ... freesia, rose, honeysuckle, violet. But go easy on it. Different people are more sensitive to smell intensity that might keep them awake. For instance, some people gag with after shave in a crowd. (Me? the more the better if Drakkor Noir or Preferred Stock). To each his own. Tailor to your senior, not yourself.
Stay away from patchouli since genetic differences cause this scent to be perceived differently. Some smell sweet aroma. Some of my friends and I distinctly smell "mold". Another friend smells 'chemicals'. If buying any fragrance for sleep, ask your senior what smells the most calming at a scent shop like Body Works. Most consider scents of food like cherry, vanilla, strawberries, chocolate, etc stimulating of appetite, not sleep. Citrus typically wakens from sleep so lemon/lime/orange and their mixes are out, unless your senior needs to snap out of it in the morning. Those are good "wake-me" scents for shower soap or shampoo. Dad might be more comfortable around scents he's familiar with like woods and after shaves. Well ... not motor oil and fish guts ... but you get the idea. semi formal or casual items to wear for women
It should be obvious: NO LIT SCENTED CANDLES. What do you want to do, burn the house down when your senior knocks it over in the night?
Experiment on yourself if you like, but remember scents are perceived differently and some people can have allergic reactions. Tailor the scent to your senior. :)