This last prohibition will require that her visitors not smoke in her home. Be sure to mention the title. I have fingernails that grow just so far, then break. The nail tips actually peel. I'm 72 and in good health.
Fingernails become more brittle with age.
This tendency is worsened by cold, dry weather and repeated hand-immersion in cleaning solutions. You may be able to reduce nail cracking and peeling by keeping your nails cut shorter. In many people, this simple solution solves the problem. Other folks have discovered that eating two or three portions of gelatin a day will strengthen the nails. Perhaps the combination of these inexpensive approaches might benefit you.