They cannot get rid of him once the living had been bestowed on him, and the living was probably bestowed by his father as patron. His father cannot deprive him of the living either -- the patron had the power to nominate, but no power to dismiss. As JA's nephew wrote in the Memoir of JA (writen during the more strict Victorian era) -- chap 10 "no one in these days can think that either Edmund Bertram or Henry Tilney had adequate ideas of the duties of a parish minister". They were both accustomed to gentlemenly pleasures, they were their patrons' sons who never had to serve as curates, they had good livings (with curates to assist them) ready for them to step into as soon as they had taken orders.