Battery, Alternator or Short?

What is your question?

Was driving to work the battery light came on, it was raining...defroster's, headlights, windshield wipers and stereo all were on...get off work sunny outside battery light still on..nothing else was on inside car all of the sudden all these lights come on I lose power and the car dies. Husband buys a new battery, battery light is still on? We went approx. 50 miles and it died again on the freeway at night. We coasted off the freeway . We sat for approx. 15 min. opened the door all lights were working inside and out took battery out to recharge and it showed 95% drain. Alternator? If so why were the lights all coming on?