My father was generous, so he indulged all my whims.
Literal
Father [topic-は] generous was [because-ので], my whims [also-も] all fulfilled-for-me.
~てくれた signals the father's action was a favor received by the speaker. 寛大 ('generous/tolerant') is a na-adjective. 気まぐれ means 'whim' or 'caprice' — the kind of word that paints a vivid picture of a child's random requests being patiently met.