The question of whether a sentence be grammatical equivales the existence of a parse tree which, when linearised, yields the original sentence.

Because the sentence is finite, it has a finite number of components, and hence a finite number of possible parse trees, so we could enumerate them all until we find one that works.

Exercise: what is the maximum number of parse trees a sentence of length N might have?

However (being an english speaker and using wetware as an oracle) a suitable witness can be found by inspection:

  and
  ├─can buy
  │ ├─Money
  │ └─of
  │   ├─if not
  │   │ ├─if not
  │   │ │ ├─many
  │   │ │ └─most
  │   │ └─all
  │   └─that
  │     ├─the things
  │     └─make
  │       ├─people
  │       └─happy
  └─if/then
    ├─doesn't [buy]
    │ ├─it
    │ └─[them]
    └─is
      ├─the fault
      └─ours