He'll give up the living, but we cannot expect him to give up boasting of his great patroness, and Longbourne will continue to be entailed on heirs male. (One does not like to think of a neighborhood in which both Mr. Collins and Mr. Lucas reside. Could even our Jane cope with such inanity?)

However, I think he'll have a bit more money since Charlotte is not the spendthrift that Mrs. Bennet is. Also, there is evidence that Mr. Bennet feels he could have set aside a bit of money for his wife and children. Lady C de B can be relied upon to tell the Collinses how to manage their money, I'm sure.

My opinion, based on people I know, NOT on the text:
Charlotte is such a sensible person that I have no doubt she will have a son. I think with a shudder of young Master Collins following his father around the parsonage. I daresay a younger son will be a rake and rapscallion. The third child, a daughter, will be named Elizabeth and will be a joy to her mother.