I agree with you that it looks like Coelogyne pulverola, although I am not very familiar with this genus. densiflora (also known as massangeana) looks a bit different...
I can't find any growing info either on internet, but did find stuff on Orchidwiz, if indeed this is the correct name.
According to Orchidwiz (if it's pulverola), it needs bright light, temps around 25°C during the day (plus/minus 6°C) and 18°C at night, all year round. 80% humidity, heavy watering while in active growth, and needs a fast draining medium. They supposedly hate repotting, which some say delays blooming up to 3 years.
Hopefully someone who actually has this plant will be able to give you more info. I'm assuming your mom owned it a while sinc she tells you it's tough. In that case, her way of growing seems pretty successful!