A grab bar looks like a fifteen-minute job on the package and a different job once the drill touches the wall. The question is not whether you can make a hole. The question is whether the bar is fastened to something solid enough to hold when Dad grabs it on the way down, and whether you can prove that to yourself before he trusts it.
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.
Find out what is behind the wall
Drywall alone does not hold a grab bar. Plan for the bar to be fastened into a wall stud, into blocking between studs, or into a backing plate that was built in before the wall was finished. A stud finder is a starting point, not proof. Before you buy anything, confirm three things: what the wall is made of (drywall, plaster, tile, or a tub surround), where the framing sits at the exact height and spot you want, and whether the manufacturer's install instructions list the anchors that match that wall type. If the wall is tile or a fiberglass surround, the fasteners and sealing are different work. Treat that as a hire unless you have done it before.
Pick the spot with Dad, from his stance
The right spot is where his hand goes, not where the bar looks tidy on a sheet of paper. Put painter's tape on the wall. Have him stand where he actually stands at the toilet, the tub edge, or the bedside, and reach for the tape the way he reaches when he is tired or getting up in the dark. Mark the height and the angle. If he will not cooperate with the test, that is information too. It tells you the bar may need to sit in a different place or that a freestanding frame may suit him better than a wall-mounted bar.
The do-it-yourself checklist
Do it yourself only if all of these are true: the wall type is in the install instructions, you have located framing at the marked spot, you have the right bit and fasteners for that wall, you can hold the bar level while a second person checks it, and you are willing to test it under load before anyone relies on it. Record the stud locations, the fastener size, and the date on a card you keep with the house papers. Check the bolts every few months, since a bar that was tight in the first week can loosen with use.
The hire checklist
If you hire it out, ask the installer these questions and get the answers in writing on the quote: Where exactly will each bar be fastened, and what backing do they confirm before drilling? Will they add blocking if the framing is not where you need it? Who patches and paints the drywall afterward, and is that included or extra? What warranty covers the installation separately from the bar itself? Are they licensed and insured for this work in your area, and can they show you the certificate? If the bar moves or pulls out within the warranty period, who comes back, and how fast? Ask those questions before you agree to anything. The answers tell you whether the job is scoped or just priced.
If Dad rents, check the lease first
Drilling into a rental may break the lease, and a landlord may have rules about who can alter the unit or who pays to repair it. Read the lease for alteration and repair clauses, get the landlord's permission in writing before any hole goes in, and ask whether the landlord wants the work done by their own contractor. If the terms are unclear, a local tenant office or an attorney can explain what applies where you live. This is a question for them, not a guess to make on a Saturday morning.
Assign the check after the install
Name one person who checks the bar on a schedule, who calls the installer if it moves, and who tells Dad what the bar is for. A bar that Dad does not trust gets ignored, and a bar that nobody checks gets loose. Put that owner's name on the same card with the stud locations and the warranty dates.
Where you need outside help finding a licensed installer in the St. Louis area, start with Local Help in St. Louis. For how we check the claims we make about home safety work, see Sources.
Next move tonight: Put painter's tape on the wall where Dad reaches for support, have him reach for it from his real stance, and write down the wall type. Then call one installer with the questions above and ask for the answers in writing before anyone drills.