He was always covered in grime, and it looked like he wasn't even being properly fed.

Literal

Always grime-covered [copula-で], meals [also-も] satisfactorily given-not [passive-ていない] appearance [copula-でした].

あか (垢) 'grime / body dirt' is specific to unwashed skin. だらけ is the suffix for 'covered in / full of.' 満足に 'satisfactorily / properly' is a na-adjective used adverbially. 与えられていない is the passive-progressive-negative — 'is not being given.' 様子でした 'it appeared / seemed' wraps the observation as external appearance. A neglect-description sentence.