Before doing anything, more analysis is needed.
Is the patio area subject to inordinate water accumulation?
For instance, if the patio is located in a corner and there are no gutters, the water flowing off two roof surfaces for over then year may be the cause. IF the patio is below grade, perhaps water diversion methods should be applied in other locations to prevent wash out that ultimately leads to patio issues.
Now, it is possible the patio was installed without proper preparation. The best solution is the bust it up and pour a new one....or bust it up and put down really nice pavers.....or bust it up and plant a garden.
If you bust is up, before doing anything else, plan a water diversion strategy that will redirect any water away from then house regardless of the condition of the patio. Perforated pipe or french drains work well when sized properly. But don't overlook the need for gutters, downspouts and peculators.