Sit on the edge of his bed and watch him stand up. That is the test. Most bed advice is written for a bed nobody is standing beside, and a father who refuses help will not hold still for a tape measure unless the check looks like part of the night. Start with what he already does: where he puts his feet, which side he rolls toward, and whether he pushes off the mattress with both hands or grabs the frame.
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 from the floor to the top of the mattress
Run a tape from the floor to the top of the mattress with the bedding he actually sleeps under. A topper, an extra blanket, or a newer mattress adds height you did not plan for, so measure the bed as it is, not as you remember it. Write that number down. Then have him sit on the edge in his usual sleepwear and check whether his feet rest flat on the floor. If they do not, the bed is the wrong height for him, and the adjustment has to move the mattress toward flat feet, not toward what looks neater in the room.
Check the stand against the chair he trusts
A bed that sits close to the height of his usual chair is easier to leave safely. Put the bed height next to the seat height of the chair he uses in the morning. If the bed is much higher, he has to drop onto the mattress and then climb back off it. If the bed is much lower, he has to push up from a deep position. Neither matches the chair he already knows how to use, and that mismatch is the moment worth fixing before it turns into a fall.
Test the landing side and the floor beside it
Pull the bed far enough from the wall to see whether he has a clear path to stand on the side he gets out of. Check that nothing hard or loose sits where his landing foot will go: a slipper that slides, a cord, a stack of books, a small rug with a curled edge. Look at the lamp switch, the phone, and the water glass. If he reaches for them from the bed, put them where his hand already goes, not where a catalog photo suggests.
Pick the fix that changes the height, not the stability
Most height problems come down to three fixes: a different mattress, a riser under the frame, or a lower or higher frame. Compare them by what each one changes. A riser alters the height but can shift the frame, so check that the bed still sits level, that the legs do not slide on the floor, and that the riser is secured to the frame. A new frame changes the whole setup and is harder to undo. A mattress change alters the feel first, and he will notice that before anything else. Whichever you choose, ask the seller or installer for the finished height in writing, measured the same way you measured the old bed, so you are comparing the same number at each step.
Make the change with him, not around him
Present the change as a fit for the bed he already has. Say the frame is shifting or the mattress has settled, then let him choose between two heights you have already measured. A man who refuses help will often accept a change that looks like maintenance. If he refuses all of it, leave the bed alone, move the lamp, the phone, and the water to the side he uses, and recheck the floor and the stand in a week.
Tonight, sit on the edge of his bed, watch how he stands, measure floor to mattress top, and write both numbers down next to the chair height you already know. If they do not match, your next call is the seller or installer for the finished height in writing. If you need local people to help with the home visit, start with Local Help in St. Louis.