That should be enough. Make sure you write a cover letter with your application ad explain the circumstance fully in the letter. Is is possible to get a letter from any of the man's family members confirming that you have gone to inquire and that htey do not know where he is? That will help. You can also have a sworn declaration signed by a lawyer that you have been solely responsible for your son. Gte a letter from his school to confirm they know you as the sole care who is responsible for him. Include receipts llike his school fees that you have paid in the past.
Add pictures of you and the child showing different stages of his growth.
