Dog i saw has dark brown mucus out of a warm, dry nose.. is coughing and moving slow.. also has formed some more 'white' appeari

Your complete post didn’t come through for some reason, but dark brown mucous coming out of a warm dry nose does not sound good. That color could come from a combination of blood and infection, which is not a good combination. I’d recommend your ex have the dog examined to determine both the exact nature of the discharge as well as its source. It might be something like a foreign body the dog has inhaled that's causing the problem or a sinus or respiratory infection.