Her closet is where her day starts: the cardigan, the coat, the shoes she can slide on while sitting down. When the rod sits above the place her hand naturally falls, she stops reaching for the clothes she wants and starts settling for the ones she can get. That is a small change in the house, and you can often make it without bringing in a contractor.
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 the line on her side of the wall
Stand where she stands to dress, let your arm hang loose, and have her reach for the hanger she uses most. Mark where her hand lands on the wall with painter's tape. Do this with her there if you can, because a rod that clears your reach can still sit high for hers. Then watch whether she can take a hanger off without lifting her shoulder or rising onto her toes. If she has to do either, the rod is too high.
What the rod is hanging from
Before you move anything, find out what holds it. Most closet rods hang from two brackets screwed into the wall. Run a stud finder along the wall and mark where the framing is. A bracket that sits on a stud, with screws long enough to bite into it, is a job a handy family member can redo in an afternoon. A bracket that relies only on drywall anchors, or sits on a plaster wall with unknown backing, is a different job, because the anchor you choose decides what the rod can safely hold.
Do it yourself when the change stays on the same wall
Lowering or raising a rod on a wall with solid framing is ordinary work. You need a level, a drill, a stud finder, screws long enough to reach the framing, and a helper to hold the rod while you set the second bracket. Once it is up, load it slowly with a full day's clothing before you trust it, and press down on the middle with your hand to test it. Then tell her plainly that the rod is for hanging clothes and not for steadying herself. A closet rod is not a grab bar, and she should not lean on it to get up, sit down, or keep her balance.
Hire it out when the wall decides the job
Call a carpenter or handyman when the change moves past the brackets. Examples include a built-in closet with shelves and doors that rub when the rod shifts, a plaster wall with no clear framing where you need it, a new height that puts a bracket near a pipe or wire you cannot see, or a request for a longer run of rod to reach the far side. If you cannot find framing where you need it, do not drill and hope. Anchors tend to fail under a full load, which is exactly when she is reaching for something.
Questions to ask before anyone starts
Ask how they will locate the framing and what they will do if they hit a wire or pipe. Ask whether the quote covers patching the old holes and painting the patches, or whether that is a separate line. Ask who removes the old brackets and whether they will load-test the rod before they leave. If the shelf above the rod blocks the new height, ask whether they will move it and what happens to the plan if the shelf turns out to be a bigger job than expected. Get the answers in writing, along with a plain description of what will be fixed and where.
Keep the change tied to her routine
Once the rod is in the right place, check it at the same time you check the rest of her day. Is she still choosing her own clothes? Does the hanger come off without a struggle? Have lower garments started to pile on the floor because she cannot reach the top? If the closet still works for her, you have made a change she can keep. If she has stopped dressing herself, the rod is not the whole problem, and that is worth a conversation with her doctor and with the people helping you plan her care. For the larger questions about who does what in the house, the local help page is a place to start.