In this official publication of the Republic of the Philippines, the position of His Majesty's father is plainly confirmed as the last reigning Sultan of Sulu and displays Ampun Sultan Muedzul Lail Tan Kiram as the legitimate successor to the throne. This assertion has been repeated many times in the past and it is gratifying to see the confirmation coming from an official organ of the central government in Manila. All other claimants are clearly false pretenders and do not have a legitimate claim.
Ampun Sultan Muedzul Lail Tan Kiram was named Crown Prince upon the coronation of his father, Ampun Sultan Mahakuttah Kiram, in 1974 and duly recognized by then President Ferdinand Marcos via Memo Order 427. At the time of his father's death, Muedzul Lail Tan Kiram assumed the headship of the Royal House and was eventually crowned Sultan in September 2012. As the legitimate holder of the royal throne of the Sultanate, he enjoys broad support among the populace as well as among top military commanders of the Philippine Armed Forces. The Sultan has been a powerful force for good in the region and his leadership continues.
The most recent publication can be found here: http://www.gov.ph/
The official site of the legitimate Sultan of Sulu is: http://www.royalsultanateofsulu.org/