So sorry to hear about your fish! Men can be so inconsiderate sometimes. Definately make him buy you a new one (finances permitting...I know how that goes)
I had a betta die of velvet last week. I got this from fishprofiles.com it was listed under freshwater fish disease.
"Velvet is a very common, highly infectious disease with a three stage life cycle similar to white spot:
Growth, spent on the skin of the host fish.
Cyst, spent on the bottom of the tank.
Free swimming infectious stage.
Each cyst divides into spores, which have up to 24 hours to attach to a host.
An attack of velvet is visible as a yellow or gold dusting on the sides and fins of the infected fish. The infestation causes severe damage to the skin and gills.
As length of the life cycle is dependent on temperature, the water temperature should be raised a few degrees during treatment. Specific treatments are commercially available. Other treatments include a 15 minute 3% salt bath."
edit: I just realized this is the same bf that was complaing about the quality of care you give your animals....(other thread) He's on a roll this week! At this rate he'll be sleeping on the couch the rest of his life!