A partnership or contract would not be included in the trust - but a share in a partnership could be a trust asset if the share was titled in the name of your father, as trustee of his trust. Or, if a partnership share exists in the name of your father, it would be a probate asset. As a nominated exeuctor/administrator, you are really not entitled to know anything about a will or trust until death of the grantor because wills and trusts can be amended before death so long as a grantor is competent.
I agree with Attorney McMahon. It appears that you are not a beneficiary yet, but you should retain counsel as your father's attorney-in-fact. Assuming your father is currently a beneficiary, your new attorney should be able to work with your Uncle Harry's attorney to uncover the information that you are seeking. Good luck to you.
This information is presented as a public service. It should not be construed to be formal legal advice nor considered to be the formation of a lawyer/client relationship. I am licensed in Connecticut and New York and my answers are based upon the law in those jurisdictions. My answer to any specific question would likely be different if I were to review a client's file and have the opportunity to interview the client. Accordingly, I strongly urge you to retain an attorney in your jurisdiction with respect to any legal matter.
The other Attorneys are correct. In addition, if your Father is declared incapacitated during his lifetime, the power of attorney will be effective. Depending on the terms in the document, you may be able to learn more about the partnership.