Brief Answer:
Infection

Detailed Answer:
Hello

Thanks for the query

There are only two things that can cause strong urine and fecal smell.

1. Dehydration.
If your mother is dehydrated then due to increased concentration of waste products there can a strong pungent odor
2 The second most common reason for a odor is infection. I suggest you to give a urine sample for urine routine test to rule out urinary infection, it is very common in the elderly

I hope I was of help, if you have any further queries please get back to me

Regards

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