At two in the morning the question is rarely about the device itself. It is whether the thing you ordered will sit in the space beside her bed, leave room to turn around, and let her stand up from it without a struggle. A bedside commode is simple to buy and easy to get wrong, because the product page was written for a room nobody in your family has seen.
Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.
Measure the gap, not the room
Start with the narrowest path she actually uses at night. That is usually the space between the side of the bed and the wall, or between the bed and a dresser. Measure the clear width at hip height, since furniture and door frames often narrow higher up. Then measure from the edge of the bed to where the seat will sit, and check whether a person can stand between the bed and the commode with room to pivot. Write those numbers down before you open any product listing.
Next, ask someone in the house to measure her seat. Have them sit her in the chair she uses most and record the height from the floor to the top of the seat cushion. Note whether she pushes up from the armrests or from the seat itself. A commode set too low or too high is hard to rise from, and that is the fit problem families most often discover after the box is open.
Compare the listed numbers to your notes
Product pages list a seat height, a base width, a depth, and usually a weight rating. Set each one beside your measurements. Do not rely on words like universal or fits most homes, since those describe a manufacturer's assumptions, not your floor plan. If the base is wider than your gap, the seat does not matter. If the seat height differs noticeably from her chair, plan a second look before you buy. Also check whether the frame folds, which side the bucket lifts out from, and how the lid opens, because those details decide whether she can use it in the dark without twisting.
Check the walk, not just the spot
A commode that fits beside the bed is only useful if the route to it is clear. Walk the path with a tape measure, or ask a local helper to do it. Look for rugs that bunch at the edge, cords that cross the floor, and a bathroom door that swings into the spot where the commode will stand. A night light along that route often matters more than the equipment itself.
Test the fit from far away
Most of this can be done from your phone. Ask for a photo with the tape lying across the gap, a second photo from the doorway looking toward the bed, and a short video of someone rising from her chair. Compare the photos to your own numbers rather than asking the person on site to decide for you. If nobody local can do the walk-through, the local help page on this site describes how an in-home check works, and the sources page lists the public material behind these checks.
Tonight
Measure the clear width beside the bed at hip height, the distance from the bed edge to the bathroom door, and the height of her seat from the floor. Send those three numbers to whoever is in the house, and ask them to photograph the route once with the lights on and once with them off.
What to leave with the doctor or therapist
Bring your three measurements and a plain description of how she stands up and sits down now. Ask whether she should use a commode at night at all, what seat height the therapist recommends for her current strength, and whether someone should watch her first transfer onto it. Ask which weight rating applies to her and write the answer down. These are questions for the people who know her condition, not for the product listing.