Are the specks on the plant scale insects? It appears to be infested with whatever that is, which would also be in the soil. Then again, this plant can tend to look like that and it may be perfectly normal. While a one-time application of 70% isopropyl alcohol is sometimes in order, I would not have recommended 'drenching' any plant with alcohol for 2 weeks, let alone 90%. Alcohol desiccates tissue.

This is a low water plant. The plant may have been over watered, leading to its current state. The rotting of leaves at the apex points to this. A plant can rot from the tip down.

I recommend you remove a few good leaves, clean off any debris (scrape off any insects), and place them upside down atop a dry soil mix to try to root them. They won't need water because the moisture in the leaf will serve as its sustenance. It is always a good idea to propagate what you can when a plant is looking ill. Next, I would take the plant out of its pot, rinse off the roots of all soil, clean off the leaves of any debris, and repot in new dry soil.

Keep the plant away from other plants, out of direct sunlight, and water thoroughly only if/when you see new growth. The point is to allow it to rest and de-stress. For future use, you may want to try BONIDE Systemic Granules on your non-edible plants. I use it with excellent results, especially so in houseplants.

You mentioned "the soil was not able to hold the plant up." Why? Are the leaves overly heavy from overwatering?

All the very best,

Maria Elena