On this side by side refrig/freezer, the freezer side is warm at the top and cold at the bottom. Do we just need a new fan ? The refrigerator side is working fine.

Why don't you remove the freezer coils cover and see if you do. It could also be the defrost heater and/or the timer and terminator (attached to heater). The only way to know is to check it out, also, clean the coils under the unit.