After Lennie dies how does that change how George plans to use his money?

The text does not give us anything concrete.  Therefore, we are left to make an educated guess. In light of this, I would argue that George will not pursue the purchase of the land. 

First, I am sure that guilt will crush him.  He just killed his best friend, or better, his only friend in a lonely world.  To seek land after this would not be consistent with George's character.  To be sure, George killed...

The text does not give us anything concrete.  Therefore, we are left to make an educated guess. In light of this, I would argue that George will not pursue the purchase of the land. 

First, I am sure that guilt will crush him.  He just killed his best friend, or better, his only friend in a lonely world.  To seek land after this would not be consistent with George's character.  To be sure, George killed him in an act of mercy, but this does not change the sorrow.

Second, the whole dream of the land was a joint venture among friends.  Hence, the element on friendship is as important as  the land itself.  So, without Lennie, George probably will not continue.  The recounting of their dream was rooted in friendship.  This is an important point to underline.  Here is snippet:

George went on. “With us it ain’t like that. We got a future. We got somebody to talk to that gives a damn about us. We don’t have to sit-in no bar room blowin’ in our jack jus’ because we got no place else to go. If them other guys gets in jail they can rot for all anybody gives a damn. But not us.”