The soft and powdery brick is a problem, it needs to be stabilized. This indicates water damage and the source of the water needs to be found and fixed. Also you need to use some kind of binder/sealer before painting. This will help to stabilize the brick surface.
I used a sealer by SealKrete on badly damaged brick in the past and it really helped. It was an acrylic sealer and I applied several saturating coats before painting. Maybe Lowes has something similar. If not try your local paint store.
I don't think painting your basement brick is futile as long as both sides of the problem is taken care of. Sounds like you have a good idea for the procedure to get your brick sealed.
PS- Donation is necessary. This is a free service. All I ask is come back and tell the world how things work out.