Dad is right about the obvious part. The water is hot. The heater works.
That does not answer the maintenance question. A water heater can produce hot water while its shutoff is hidden, its drain path is blocked, its service record is missing, and nobody knows whom to call when water appears underneath 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.
Do not open with replacement. Open with ownership.
Tell him you are not trying to condemn the heater. You want to identify four things: what feeds it, what stops it, where leaking water would go, and who takes the first call. That is a house problem, not a referendum on whether he can live there.
Start with the whole water route
Stand where the heater stands and follow the route with your eyes. Identify the cold water pipe entering the unit, the hot water pipe leaving it, and the valve intended to stop water entering the tank. Do not assume the nearest handle is the right one. Trace the pipe.
Then find the main water shutoff for the house. The local valve may be stuck, mislabeled, or unreachable once water is spreading. The main shutoff is the second line of defense.
Check whether each valve can be reached without moving storage, climbing over equipment, or kneeling behind the heater. If Dad cannot reach it, the valve is not part of his emergency plan. It is scenery.
Do not force a valve just to prove it moves. A neglected valve can start leaking when disturbed. If its condition is uncertain, make valve testing part of a plumber's visit.
Find where the first gallon goes
Look beneath and around the heater. Is it sitting in a drain pan? If so, follow the pan outlet. A pipe that ends against a wall, points uphill, or disappears behind boxes has not yet proved anything.
Find the floor drain if there is one. Check whether the path from the heater to that drain is open. Cardboard cartons, rugs, paint cans, and stored papers turn a manageable leak into a house cleanout.
If the heater sits above finished space, note what is directly below it. A stain downstairs may be the first visible warning. Decide who checks that ceiling and who moves anything valuable out of the likely water path.
Look for rust, dampness, mineral residue, warped flooring, or water tracks. Do not diagnose the source from one mark. Pipes, fittings, the tank, and nearby equipment can all put water in the same place. Photograph what you see and send the same pictures to anyone asked to inspect it.
Separate a drip from the wrong kind of emergency
Water on the floor calls for a quick source check and a shutoff plan. A smell of gas, hissing near a gas connection, smoke, sparking, or scorching calls for distance and emergency help. Do not operate switches, light flames, or begin taking equipment apart to investigate a suspected fuel or electrical problem.
Know whether the heater uses gas or electricity. For a gas unit, identify the gas shutoff location without experimenting with it. For an electric unit, identify the labeled circuit without opening panels on the heater. If the electrical panel label is unclear, that becomes a job for a qualified electrician, not a guessing contest during a leak.
The temperature and pressure relief valve and its discharge pipe are safety equipment. Do not cap the pipe, plug it, or treat dripping as something to silence. Record where the discharge pipe ends and ask a qualified plumber to inspect anything that appears altered, blocked, damaged, or actively leaking. The site's source desk points readers toward the public agencies and standards behind these basic safety lines.
Give the maintenance call a script
If Dad accepts an inspection, make the request narrow enough that he knows what he is agreeing to. Ask the plumber to identify the water shutoff, assess whether it operates safely, inspect visible connections, inspect the relief valve and discharge route, check the drain pan and drain path, and state what maintenance is appropriate for this specific unit.
Ask for findings in three buckets: working as observed, needs service, and needs a separate trade or utility. That keeps a vague visit from ending with a vague warning.
Before work begins, ask what will be shut off, whether hot water will be unavailable, who will relight or restore the unit, and what the plumber will test before leaving. If any permit or inspection is required for proposed replacement work, ask who is responsible for arranging it.
Do not approve flushing, valve operation, or parts replacement merely because those tasks appear on a generic maintenance list. The right work depends on the unit, its condition, its installation, and the local water system. Ask the person inspecting it to explain what they propose and what problem that work addresses.
Put one name beside every job
Write a short water heater card. It can live on the inside of a nearby cabinet door, in Dad's house file, or with the emergency contacts. Include:
Water heater fuel: gas or electric.
Local water shutoff location.
Main water shutoff location.
Gas shutoff or electrical circuit location.
Floor drain or pan discharge destination.
Plumber's name and phone number.
Person authorized to meet the plumber.
Person who will move stored items from the water path.
Location of photographs, service records, and any warranty paperwork.
Dad does not have to hand you control of the house. He can keep the call, the decision, and the keys. The point is to remove the scavenger hunt from the moment when water is already moving.
If he wants a local starting point rather than a family debate, use Local Help in St. Louis to identify the appropriate public or community route. For the broader method of turning a refusal into one limited job, use Start Here.
The next move tonight
Take one photograph showing the entire water heater and the floor around it. Take a second showing the cold water shutoff. Then ask Dad one question: "If water is running from this thing, who do you want making the first call?"
Put that person's name and number beside the two photographs. That is tonight's job. The heater can keep working. The plan no longer has to depend on luck.