Step-son

His step-son is the heir to his riches.

Source: tatoeba (8955741)

That's Tom's step-son.

Source: tatoeba (9362922)

John Cool, a resident of Warrensville, twelve miles east of Clveland, made an attack upon two step-sons, Edward and Henry Quayle, aged twenty and eighteen years, with a butcher knife, on Saturday evening, and inflicted wounds upon both to such an extent that Henry died in four hours and Edward cannot live long.

Source: wiktionary

The menu, as conceived by chef Joel Somerstein -- Ms. Somerstein's step-son, and formerly a chef at the Hotel Pierre and Jean-Georges Vongerichten's Lafayette -- is a mix of standard dishes (free-range chicken, sweetbreads, salmon with potato blinis) with a smattering of international tastes.

Source: wiktionary