This isn't a close out on the thread, but some more info.
It is possible to follow the instructions and process with Treasury to send these to them - after opening a TreasuryDirect account - however, not all circumstances are covered online - and, after waiting three hours on hold - I looked for other, more timely alternatives.
First, assuming my 50 years of membership and solid accounts with Navy Federal Credit Union would be worth something, I called and worked with their very nice and knowledgable national representatives. However, since my sister does not have an account with them, they would work with only $1,000 per day - and, she would need to sign each one in their presence, probably inside their building. After several discussions, their internal policy being noted at least 20 times, they were utterly unyielding - even when I finally noted that I would be vindictive in the only way I could - terminating any future relationship with Navy Federal. Again, the answer was no.
So, I went to my sister's credit union, Pen Air. They worked out quickly that she could sign them all at home (my wife and I will fill in the address info on each one), then present herself for identification in the car ONE TIME, and they would process the bonds and deposit the amount to her account. This would still take them on the order of an hour of time. They set up an appointment for tomorrow at 1000. Once my sister gets the OK, she can deposit the funds to Fidelity via app.
Sigh - not at all what I was expecting from NFCU - literally a lifetime of goodwill tossed due to "our internal policy."