Lele has an affection for his yeye (paternal grandfather) since young.
It's easy to see why.
Yeye takes him for walks often (almost daily).
Yeye lets him do stuff like taking the driver's seat of his car, meddling with the car radio and other gadgets, riding on his motorcycle, playing with the remote control battery covers and other things.
Yeye is pretty humorous and always makes him laugh.
Mama thinks Lele loves his Yeye because he dotes on him so much he seldom say no to him.
For example, if there Lele finished a piece of apple and wants some more, he will go to Yeye and be very persistent in fussing. Even if he told him no, Lele would continue insisting, probably because he knows that Yeye might give in if he tries hard enough.
If it were mama or others telling him "No.", he will be less persistent.