Nail weakness and joint pain can be attributed to various factors, and it’s essential to consider multiple aspects of health. Some common reasons for nail weakness and joint pain include:

1. *Nutritional Deficiencies:* Inadequate intake of essential nutrients like biotin, iron, and vitamins can affect nail health.

2. *Arthritis:* Joint pain, especially in the knees, may be associated with arthritis, such as osteoarthritis or rheumatoid arthritis.

3. *Hormonal Changes:* Hormonal imbalances, especially in women going through menopause, can affect nail and joint health.

4. *Inflammation:* Chronic inflammation in the body can lead to joint pain and may affect nail quality.

5. *Infections:* Fungal or bacterial infections can impact nail health.

6. *Dehydration:* Lack of proper hydration can contribute to brittle nails.

7. *Overuse or Injury:* Continuous stress on the joints or previous injuries can result in pain.

It’s crucial for your mother to consult with a healthcare professional, preferably a rheumatologist or a general practitioner, to determine the specific cause of these symptoms. Blood tests, imaging studies, and a thorough medical history can aid in diagnosing the underlying issues. Once the cause is identified, appropriate treatment options can be explored to improve both nail and joint health. May Allah grant her good health and well-being.