。
He can do whatever he likes because he's wealthy.
Literal
Wealthy be-[because-ので], he [topic-は] anything do-[nominal-ことができる].
何でも ('anything, everything') is an indefinite with the -でも suffix ('even, any'). することができる is the explicit potential form using ことができる — more formal than the contracted できる. Together 'can do anything.' The ~ので causal marker attaches to 裕福な by way of the copula-dropping な-adjective form.