When the head of the household is no longer listed, don't assume he/she is dead. It's possible that the former head of household is now living with one of the children.
Death Records can be the least accurate records depending upon the knowledge of the person reporting the information about the deceased. How much do your children know about you?
The lack of information in this source infers an answer to this question.
[Sources & Evidence]
The "Social Security Death Index" is an online searchable database. It only includes the names of deceased individuals whose deaths were reported to Social Security. Beginning in 2014, rules governing the "Social Security Death Index" changed. Records for the most recent 3 years are not available.
When writing to a relative for information, make specific requests. Don't ramble! Offer to share your information.