Thank you for the query.
Soft, smelly stools can be caused by pancreas
disease due to lack of pancreas enzymes responsible for fat digestion. This undigested fat causes bad smell and soft consistence of the stool.
Such symptoms can be also caused by intestines bacterial infection. Such bacterias can cause accelerated stool passage.
It is advisable for you to have fool blood work with pancreas and liver
tests, stool tests, urine analysis and abdominal ultrasound
Hope this will help.