"though to the last always assuring his wife that he should not go;..."See in text(Chapter II)
It is comical that Mr. Bennet was one of the first to wait on Mr. Bingley because his argument with Mrs. Bennet was based on his staunch refusal to make the visit. Mr. Bennet clearly enjoys teasing his wife; he always intended to make the visit, but made a point to assure Mrs. Bennet that he wouldn’t go. He is perhaps a little irritated by her “poor nerves,” since she tends to use them to get her way. He may also find her amusing because it is easy to get a rise out of her.
“Ill” is being used to mean “poorly”; Mr. Bennet is saying that Kitty is bad at timing her coughs. This is another classic example of Mr. Bennet’s sarcasm: this time, he is teasing Mrs. Bennet for scolding Kitty as though Kitty is coughing intentionally.
"and I am glad to find that you do not depend on her serving you..."See in text(Chapter II)
Mr. Bennet is teasing Mrs. Bennet because she is being hypocritical. She resents Mrs. Long because she’s sure Mrs. Long is trying to set up one of her nieces with Mr. Bingley. She calls Mrs. Long a “‘selfish, hypocritical woman’” even though she is being selfish and hypocritical herself. Mr. Bennet seems to recognize this hypocrisy and sarcastically says he is “‘glad’” that his wife isn’t about to turn to Mrs. Long for help.
