I'd go so far as to change the passwords completely and put a paper copy in a safe deposit box and have it noted in your will along with the key location if it's not information you want her to have right now. Otherwise, just tell her if she ever needed these passwords, they're in a safe deposit box and here's a key.

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1980 300TD-China Blue/Blue MBTex-2nd Owner, 107K (Alt Blau) OBK #15
'06 Chevy Tahoe Z71 (for the wife & 4 kids, current mule) '03 Honda Odyssey (son #1's ride, reluctantly) '99 GMC Suburban (255K+ miles, semi-retired mule) 21' SeaRay Seville (summer escape pod)