有一句话看不懂,关于哈利波特里面的人物的,Lupinisawonderfulteacherandaverynicemanbuthehasafailingandhisfailingisthathedoesliketobelikedandthat'swhereheslipsupbecausehehasbeendislikedsooftenthat

　　有一句话看不懂,关于哈利波特里面的人物的,

　　Lupinisawonderfulteacherandaverynicemanbuthehasafailingandhisfailingisthathedoesliketobelikedandthat'swhereheslipsupbecausehehasbeendislikedsooftenthathe'salwayssopleasedtohavefriendssohecutsthemandawfullotofslack.(Lupin是一个人名字)

　　这段话最后一部分是不是有问题?如果是,有没有英语高手能够看懂它是什么意思?最好能推测一下作者想要写的究竟是什么话?