Grab bars come in three basic mounts, and each one fails in a different way. Packaging tends to put the strongest words on the front, so the useful comparison is what the bar is fastened into and whether it passes a test you can run in the bathroom yourself.
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.
Three mounts, three ways to fail
Suction-cup bars hold only as long as the seal stays intact, and the seal is affected by dirt, moisture, temperature, and age. Many manufacturers say in their instructions not to rely on suction for support, so read that line before you buy. Bars fastened with expansion anchors or toggles into drywall or tile can pull out under sideways force, especially over a hollow tub surround. Bars screwed into studs or solid blocking hold as well as the framing does, which is why the framing is the real question.
What to compare on the package
Look for the stated load rating and what it was tested for. Check whether the instructions name the wall material it is designed for. Compare the grip diameter, the finish, and the length, and whether the bar reaches a spot you can actually use from the tub edge or the toilet. Check whether the mounting flanges hide the screws, what hardware is in the box, and what the warranty covers. A bar with no mounting hardware named is not a comparable product.
What the wall has to be
Tile over cement board, tile over drywall, a fiberglass surround, and plaster each take a different fastener. Find out whether the shower wall was built with blocking behind it. If you cannot tell, ask someone who can open the wall or inspect it, because that answer decides which mount is safe.
The test you run yourself
After installation, take hold of the bar with your full weight and press outward, then pull down and sideways. Have a helper do the same while you hold steady. Any movement, creak, or lifting at the flange means the mount is not sound. Repeat the test after a week and after the first deep clean, because screws and seals loosen over time.
Dad's side of it
A suction bar looks like the easy fix, and he may prefer it for that reason. Tell him the truth: a bar he can see is fastened into framing is one he can trust, and the test takes five minutes. Let him run the test himself so the decision is his.
The next move
Before buying anything, find the framing in the bathroom wall with a stud finder and a small test hole, then write down where it is. Buy the mount type that matches what you found, and run the full-weight test before anyone leans on the bar.