Agreed. As proposed, it appears to be a basic contract. It appears that it was a basic contract when EFW and his ex mutually agreed orally to split the costs of college 1/3 to 2/3.
Although (potentially) enforceable at its most basic, it is best if there is a written document that fully and clearly defines the intent of the parties so there is no misunderstanding later as to what exactly is included in the 1/3 and 2/3. This becomes more important when all of the various and assorted college bills need to be paid.
It seems to me Q, that you may have alone touched on the essential legal issue here, meaning
"certainty of contract".
Perhaps knowledgeable contributors might provide their views as to the enforceability of such a proposed
writing * giving attention to the principal of contract law requiring certainty of terms.
That is to say, would the wording
"kid's college costs" (or similar expressions without limitation or nature of the costs, state or out-of-state tuition, etc., etc.,) be sufficient to bind the father to his proposed promise? Can there be mutual assent or a meeting of minds when the terms lack reasonable certainty?
Section 90 Restatement of Contracts 2nd would have the father bound to his proposed promise to absorb 1/3 when it would "
induce action" on the part of the promisee mother, but
only of a "
definite and substantial character." Which brings me to full circle:
Are terms "kid's college costs" sufficiently definite to form an enforceable contract between the parents? I think not. And if it is not binding between them , then it would not be enforceable by the proposed beneficiaries. (See: Restatement of Contracts 2nd Section 309)