Where’s the evidence hes foreignthink he's foreign too, but what could that mean for contemporary Upper Egyptian genomes? A cool 20% in Lower Egypt, 30% in Upper Egypt, 60% after first cataract (pre-Noba-admixed Kulubnarti - contemporaries of Meroitic state - were probably about 40% Nile Cushitic), and almost 100% nearing the 4th (Kadruka). A believable cline if one were to take a look at the osteology.
If you look at the physical data you’ll see that some old kingdom northern Egyptian samples cluster closest to late period Egyptians.
This has been known since the beginning of Egyptian bio anthropology