My SMC keeps corrupting, even after I reset it
SMC problems could be related to the battery itself.  That age of laptop doesn't have a separate battery - as in the average non-Apple motherboard which has a CMOS battery on the motherboard, so SMC would be using battery power to store settings.

If the battery's shot, SMC loses it's settings at whatever point the battery drains itself. 

See if you can borrow another of the same model with a healthy-ish battery to test with for a bit...