Mediterranean palm has brown tips on fronds
Severe heat this summer 115+. Frond tips started turning yellow. Started watering more. Tree is getting worse. Too much water? Maybe needs fertilizer?
Your Palm may have been sunburned from the extreme sun and heat.
If possible shade the plant from the harshest sun of the day. If the Palm is well established it likely is accustom to the water fall. Do not overwater.
Mulching will help with moisture retention.
You should not try to fertilize into health. You should only fertilize in the growing season with a Palm fertilizer.
You can trim away lower branches that are aging or dead.