You mean "testator" (the maker of a will) not a guarantor which deals with loan agreements.
With that being said, the new will supersedes the old will (since newer in time) and it appears that you had it properly witnessed and notarized. All looks good except for can happen next -- let me explain:
If the testator is elderly then they are potentially subject to undue influence or duress -- especially if there is a person (the caretaker) who is in a confidential position relative to the testator. In all likelihood the two disinherited children will challenge the new will on these very causes of action. They might prevail unless you take additional steps to fend off such allegations. Did an independent attorney and doctor evaluate the testator so they could execute an affidavit (contemporaneously) that he was of sound mind and understood what he was doing?
Was the caretaker present when the new will was signed? Potential intimidation if so.
is there any videotape of the will signing showing the demeanor and competency of the testator to fend off arguments to the contrary?
My answer is not intended to be giving legal advice and this topic can be a complex area where the advice of a licensed attorney in your State should be obtained.
There are special rules in the probate code about caregivers. If the boys attack the will they will be successful. The caregiver is a disqualified person and without a certificate of independent review, the Will will fail. In addition, the facts sound like undue influence should be easy to prove without the caregiver statutes. Im guessing by the rhetoric that this is written by the caregiver.
The general advice above does not constitute an attorney-client relationship: you haven't hired me or my firm or given me confidential information by posting on this public forum, and my answer on this public forum does not constitute attorney-client advice. IRS Circular 230 Disclosure: In order to comply with requirements imposed by the Internal Revenue Service, we inform you that any U.S. tax advice contained in this communication (including any attachments) is not intended to be used, and cannot be used, for the purpose of (i) avoiding penalties under the Internal Revenue Code or (ii) promoting, marketing, or recommending to another party any transaction or matter addressed herein. While I am licensed to practice in New York and California, I do not actively practice in New York. Regardless, nothing said should be deemed an opinion of law of any state. All readers need to do their own research or pay an attorney for a legal opinion if one is necessary or desired.
As a practical matter, it's almost impossible to uphold a handwritten will that favors a non-family caregiver. The Probate Code makes caregivers disqualified from receiving an inheritance unless certain conditions are met. You are almost never going to see those conditions met with a handwritten will.
The caregiver here is very likely going to end up in probate court facing charges that is guilty of undue influence. And, unlike a criminal case where you are "innocent until proven guilty," caregivers are "guilty until proven innocent." Like I said, it's not going to work. Not likely.
This is legal information only and not meant to provide legal advice. Many issues that seem straightforward at first are often complicated by facts not revealed in a hypothetical posed by a member of the public. You should always consult directly with your attorney in order to ensure the issue is thoroughly discussed and that the proper course of action is taken.