Hello dear, welcome to Ask a doctor service. I read your question and here is my advice. The dry mouth and brittle nails are sign of sjogren syndrome. *Keep the nails short. This prevents the nails from catching on things or acting as a lever and causing further damage. *Protect the nails when performing wet work (like washing dishes) by using rubber gloves and cotton glove liners. *Avoid excess contact with water or chemicals (including nail polish remover) which can cause dryness. *Use moisturizer on your nails multiple times per day and reapply the moisturizer after your hands come in contact with water. You can use the same moisturizer used for your dry skin. *Steer clear of cosmetic products such as artificial nails and nail wraps which can cause damage For dry mouth *keep hydrated *good hygiene can help *chewing a sugar free chewing gum *mosterise air *mosterise lips Hope I have answered the question. Let me know if I can assist you further.