Oil pump replacement on '90 corolla

My brother's got a 1990 Corolla and his oil light's been coming on a lot lately (at idle and under deceleration mostly). He talked to a mechanic who told him to replace the oil pump. First, do you think that that's the right thing to try? Second, how difficult is oil pump replacement on this car - I'm sure I'll have to drop the oil pan to get to it, but I saw somewhere that I'll need to support the motor with a hoist to take the pan off...any truth to this, or just bs?