I always love to see fan art of Mufasa and Simba together. They were so close. I loved in some scene's in the lion king, were you could see Mufasa's features in Simba. Even though Mufasa died, Simba lived to follow in his 'pawprints' the bond still went on.
It seems as though Simba never quite got over his father's death, especially since Scar had lied to him about the truth about Mufasa's death. At least Simba knows his father is looking down at him from the sky (and stars at night), just like all the great lion kings of the past have to Mufasa and the generations before him.