I am so sorry to hear of your mother's condition. I would venture that her CHF is quite possibly the result of medications that she may have been on. This was the case for my mother when she was in her 80's. My sister and I convinced her to get off of almost all of her medications and most of her CHF condition went away. She lived to be 94.
I send my prayers for your mother and for you.
There are things available that can quickly kill many bacteria but they are not approved for use on humans or animals. I would suggest that Colloidal Silver can be helpful but at this late stage, it may not be enough.
There is a device called the Magnetic Pulser that may also help. You would need the strongest available, preferably over 20,000 Gauss. Not sure who has one that strong.
Ubiquinol is very important for the mitochondria that provide energy to the heart. Also tocopherols and tocotrienols mat be helpful. Vitamin D-3 and K-2 are probably low, they need to be optimal, not just normal.
Since I have no financial involvement in the above, I am free to mention. I am not allowed to discuss or suggest any products that I sell due to oppressive US laws.