he made himself indispensable to the parish priest
not to be dispensed with; essential; "foods indispensable to good nutrition"
essential: absolutely necessary; vitally necessary; "essential tools and materials"; "funds essential to the completion of the project"; "an indispensable worker"
unavoidable; "the routine but indispensable ceremonies of state"
(indispensableness) indispensability: the quality possessed by something that you cannot possibly do without
A thing that is not dispensable; a necessity. [from 17th c.]; Trousers. [from 19th c.]; Not admitting ecclesiastical dispensation; not subject to release or exemption; that cannot be allowed by bending the canonical rules. [16th-17th c. ...
means something that’s so important you can’t do without it. What’s the word?