He's a good bassit but I don't know why leaders choose him over their own in studio.
He's unanimously known as the best bassist Congolese music has ever seen. The bassists of bands, out of respect, accepted him guest playing without malice. On top of that he's esteemed because of his humbleness.
In 90's, despite his fame, he preferred to live in Matonge and was very welcoming to fans and aspiring bassists (the ones found in bands today), often giving lessons.
Some of the best bass works ever in African music can be found in Empire Bakuba/Pepe albums of the mid-90's.