The downspout is the part of the house nobody thinks about until the walk turns to ice outside the side door. Water leaving the gutter has one job, which is to get away from the foundation and away from the path your father uses to reach the car, the bin, or the mailbox. When it does not, you get pooling, ice, and a surface that looks dry until it isn't.
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.
Trace the route before you touch anything
Follow the water from the gutter outlet to the point where it leaves the pipe. Note whether it empties onto a planting bed, bare soil, a slab, or the walk itself. Check for any elbow that sags, any section that has pulled out of its bracket, and any joint that has split. Look during or right after rain if you can, because a dry day hides the problem.
Check the extension and the splash block
An extension should carry water past the edge of the planting bed and set it down on ground that slopes away from the house. A splash block is a short, flat channel that breaks the force of the water so it does not dig a trench. Test what you find against that standard. If the water lands within a step or two of the foundation, or where a person would walk, the route has failed even if the gutter itself is clean.
Decide who owns the fix
Most of this is a one-person job with a ladder and a few sections of pipe, and it can stay a family job. The real question is who keeps it working. Name the person who clears the outlet after leaves fall, the person who checks the route after a hard rain, and the person who calls for a repair if a section cracks. If nobody holds those three jobs, the downspout will fail on its own schedule and the failure will land on the walk. Dad may say the gutters are fine. Walk the ground instead of arguing about the gutters.
What to ask or compare before you buy parts
At the hardware counter, ask for pipe and fittings that match the diameter and material you already have, not whatever is on the shelf. Measure how far the water must travel to clear the walk, then compare that distance against the extension length you are considering. Check whether the ground outlet is fixed or swings, since a swinging outlet can send water back toward the path. If the grade near the house slopes toward the foundation, an extension will not solve it. That is a grading question for a contractor, not a pipe question.
The next move
Tonight, walk the route from the gutter to the ground with a flashlight, mark every spot where the water lands, and write those spots on an index card. Then put one name next to the outlet check and set the first inspection for the next rain. For how we check what goes into these pieces, read How We Write. If the grade is the problem, Local Help in St. Louis lists who to call.