Some boxers fast to lose weight so as to fight in a lighter- weight class and they combine this aim with the intention of doing this act of worship. What is the ruling of Sharia on this?

My mother is seventy years old. Five years ago, she became diabetic. However, she observes fast and offers night prayers comfortably. A year ago, she underwent gastrectomy, so physicians recommended that she have 7-9 meals throughout the day. They even stressed that her doing so is of extreme importance to her health. What is the ruling on her fasting during Ramadan?

What is the ruling on Ramadan moon sighting differences amongst the scholars where some say that each country has its own moon sighting while others say that all Islamic countries have the same moon sighting?

Should the wife seek husband's permission to observe voluntary prayer as she does in voluntary fast? Or this is limited to the latter?

How to have a Valid Intention in Prayer and Fasting?

Is there a room for Ijtihad (juristic opinion on a matter on which there is no explicit text from the Quran or the Sunnah) in Islam to review the permissibility of exempting a Muslim from fasting once he becomes sixty years old?