English to Spanish Art/Literary Religion 19th century book; Christian mothers

It requires, indeed, but a very little experience of soldiers or sailors, children, servants, or any other kind of dependents, or even of companions and superiors, to show that this good humor, on the part of those whom we wish to influence, is the best possible coadjutor* to our schemes of management, whatever these may be.
*Coadjutor-one who aids another; an assistant; a ***fellow-helper***; associate.
¿Y cómo traduciríais aquí 'associate'?