Taking his coming wealth (i.e. his "expectations") for granted, Pip keeps spending extravagantly and inspires Herbert to as well. The two go into debt. They join an expensive social club, the Finches of the Grove. Bentley Drummle is also a member. Pip wants to cover Herbert's expenses himself but knows Herbert would be too proud to accept the offer. Even as the boys fear for their finances, they spend prodigiously and unwisely. They periodically tally up their debts. This makes them feel they are in control when in fact they do nothing to curb their spending habits.
Pip continues to be hungry for material status markers, spending recklessly to acquire them. Social clubs like the Finches are similar status markers. Pip and Herbert join the club for the social caché of membership. Pip's desire to cover Herbert's expenses seems generous, but Herbert probably wouldn't have such expenses if Pip hadn't helped turn him into a spendthrift in the first place.
After one such evening of adding up debts, Pip receives a letter signed Trabb & Co. informing him that Mrs. Joe has died and inviting him to her burial next week.
Pip has completely fallen out of touch with Joe and Mrs. Joe. He had no idea Mrs. Joe was dying. He has completely lost touch with his past, and, by extension, with himself.