What about “he was no less dear to his parents on account of other things than on account of his being their son”? I think the natural thing in English would be to use a different structure and say something like “he was dear to his parents for other things as much as he was for being their son” (although that particular attempt’s not very good).
“The son died, beloved for his extraordinary good looks, for his matching modesty, and for other things by his parents, not just because he was their son.”