The questions you haven't directly answered are as follows:
1. Beneficiary of what?
2. Was any of this in writing?
The inferences I reach based on the rest of the thread are that you had an agreement for him to make you a beneficiary in his will and that none of this is writing.
If that's correct, you have a serious problem. As you appear to have described the agreement, he agreed to make you a beneficiary, but that doesn't tell anyone what you were actually to receive. I could choose to designate the lawyer in the office next to me as a beneficiary in my will by leaving her $1.00. Unless you had an agreement for him to leave you a specific dollar amount or percentage of his estate, your agreement would almost certainly be unenforceable for uncertainty.
You told us that, at one point, he had named you in his will, but you didn't provide any detail. It's conceivable that a court might accept that as evidence of your agreement, but one would need to read the superseded will to opine intelligently about that.
It seems to me that your best chance would be a claim for something called quantum meruit, which would be the reasonable value of your services rendered. You'd only get paid for services provided within the limitations period, which would only be a few years before the guy dies. Note that, by saying "best chance," that doesn't mean I think you have a good chance.
Better than that would be a discussion with the guy about the alleged agreement. "Somewhat confused" doesn't mean legally incompetent.