The dryer vent is one of those jobs that never shows up on a list until a load takes much longer than it used to. Treat it as a task with an owner, whether that owner is you on a visit, a hired helper for the easy parts, or a duct cleaning service for the rest.
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.
Signs worth checking
Look for loads that take noticeably longer, clothes that come out warm at the end of a cycle, lint built up around the dryer's back or the laundry room, and an outside flap that does not open freely. None of these is an emergency by itself, but each is a reason to look before the next cycle.
Decide what you can reach
Walk the route before you buy anything. How long is the run from the dryer to the outside wall, and does it have bends? Can you reach the outside flap from the ground without a ladder? Is there a roof vent instead? If the answer to the ladder question is no, the outside work belongs to someone else, and you should not plan for her to do it.
The do-it-yourself version
A vent brush kit from a hardware store, a vacuum with a hose attachment, and a few minutes with the dryer's manual are enough for the parts you can reach from inside. Turn the dryer off and unplug it before you pull it away from the wall. If it runs on gas, the gas supply must also be shut off, and the reconnection should be checked by someone qualified before anyone runs a load. Clear the lint trap, the area behind the trap, and the hose at the back of the dryer. Check that the outside flap opens and closes without catching.
The hire-it-out version
When the run is long, has bends, or needs a roof or wall vent cleared, book a duct cleaning service. Compare them on what they will do, not how they describe it. Ask whether they clean the full run from the dryer to the outside, whether they check the flap and the outside cap, whether they give a written scope before the work starts, and whether they show you the before-and-after of the duct. Ask what is not included before you say yes.
Who does what
A non-medical caregiver or a neighbor can pull the lint trap, wipe the surfaces you can reach, and report what the flap looks like. Climbing, pulling the dryer away from the wall with a gas line, and any roof work stay with a licensed person or with the family.
What to do tonight
Ask her when the dryer last took longer than usual, and whether the laundry room feels warm after a cycle. Have her or a helper look at the outside flap while the dryer runs, from the ground, and report whether it opens. Then ask the doctor one question before the visit: if her balance or breathing makes lifting the dryer or using a ladder unsafe, what should the family avoid doing themselves.