Meaning of a sentence from the novel The Invisible Man

She had cooked the ham and eggs, laid the table, and done everything, while Millie (help indeed!) had only succeeded in delaying the mustard. And him a new guest and wanting to stay! Then she filled the mustard pot, and, putting it with certain stateliness upon a gold and black tea-tray, carried it into the parlour

What does the bracket mean here? ((Help indeed!)) And also the line

And him a new guest and wanting to stay.

I'm having a hard time figuring out what these two things mean, so any help would be appreciated.

(Help indeed!) is ironic. Millie is obviously so far from being useful that the only thing she has done is prepare the mustard more slowly than the landlady could have done even while she was doing everything else. This is particularly vexing for the landlady since the man for whom the breakfast is being prepared is a new guest who is looking for permanent accommodation and the landlady wants to impress him favourably.

We know this because Wells says "And him a new guest and wanting to stay." In this case the "And" ties the information about the guest to the frustration of the delayed mustard meaning that the frustration is exacerbated by her desire to impress the new guest.

The "And him " structure is a bit dated now but used to be used a lot in lower class speech, particularly when there were issues of social class involved. For example "I was talking to Mr Peach in the parlour when our Jimmy came bursting into the kitchen swearing like a trooper! You could hear him all over the house! And Mr Peach being the Methodist Minister! I could've died!"

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.