جَاءَنِي رَجُلٌ عَالِمٌ أَبُوهُ — A man whose father is learned came to me.
جَاءَ: past verb, -nī its object.
رَجُلٌ: nominative subject.
عَالِمٌ: nominative relational adjective of rajulun.
أَبُوهُ: agent of the active participle, nominative with wāw (one of the six nouns); -hu is mudāf ilayh referring back to the man.
It is the father, not necessarily the man, who is learned.