Oil indicator on the dash, if the sump is full, could be a terminal oil pump failure, a well-known problem that crops up in some cars. First, someone would need to trace the oil pressure sending unit wiring to make sure it's not shorted on something. Second, listen closely to the engine when it's running, if there are any slapping sounds other than the usual diesel rattle, the oil pump chain is not turning the oil pump sprocket. Next step would be to remove and cut apart the oil filter looking for metal particles inside. If there are any, the car needs a new engine.
ABS light could be a cracked reluctor (toothed) ring on the rear axle. Not hard to get a replacement but installing it is not for the novice as the axle has to be removed.
As for value, if it actually has both of those problems, well under $1000.