The symptoms you describe could be those of several different causes. It would be helpful if we knew for sure what kind of plant it is, by the way. Some plants are associated with predictable problems.

IF it is a palm, they can be extremely prone to spider mites, which cause the leaves to dry up and turn brown. Indoor palms are also susceptible to hidden mealybugs and scale insects.

The dessicated foliage could also be caused by the fact that the potting medium has become useless. It MIGHT help if you put the plant in the bathtub, filled it up part way with water and let the plant soak for several hours.

Peat-based potting soils can loose their structure after a period of time. Add to that the fact that most people don't water correctly, but give their plants a little sip here and there rather than drenching the whole container volume with water. The former practice causes the potting medium to dry up (permanently) and become hydrophobic. A good, long soaking can help hydrate the soil again.

As a general rule of thumb, the typical potting medium has a useful life expectancy of about a year before it begins to collapse on itself. One of THE most important characteristics of a good medium is porosity. Once that's gone or has become limited, the plant can do very little but struggle from day to day.

Fertilizer should never be given to a plant as 'medicine', but only when you know that it is probably deficient. If you've not been in the habit of providing some form of nutrition to the plant, then you better jump on that bandwagon. YOU are the only way that this plant will obtain what it needs for survival.

SO! Do a careful inspection of your plant for spider mites, mealybugs, and scale insects. Give the plant a leisurely spa treatment in a tepid bath. Feed it lightly if you haven't done so in a very long time.

Pictures of the patient would be helpful.