Help indeed! is a comment on the quality of services the help (Millie) was delivering. Help is an old-fashioned title for a domestic worker:
one who serves or assists another (as in housework)
The idea here is that Millie is technically the help, but she's not helping much. The "indeed" marks the narrator's disbelief:
: without any question : truly, undeniably —often used interjectionally to express irony or disbelief or surprise
The next sentence emphasizes that Millie is being so unhelpful even to a new guest:
And him a new guest and wanting to stay!
This corresponds to Oxford English Dictionary entry 9b for "and, conj.1, adv. and n.1.":
9 b. Introducing a subordinate clause with different grammatical subject from the main clause and either a participle as verb or a complement with copular verb understood, expressing the circumstances of the action described by the main clause. Cf. me pron.1 6a. Now regional (chiefly Irish English).
Here's an example:
1992 P. McCabe Butcher Boy (1993) 157 : I seen two of her other wains running about the street last night..and them with hardly a stitch on them!
The pronoun following "and" (him, them) is often in the objective case, but it could be in the nominative too. In either case, the sense is that she's being lazy when he is a new guest that she ought to be helping more.