As an ex-spouse, your legal rights and responsibilities towards your former husband generally end after the divorce. This includes decisions about how he is taken care of during his old age. Typically, once divorced, each spouse's life and affairs are considered separate, and they are free to make their own decisions without the involvement of the other.
Your ex-husband's care during his old age would primarily be the responsibility of his current wife, and it would be up to her and any legal representatives or family members to make decisions regarding his care. As an ex-spouse, you usually do not have a say in these matters.
However, please note that laws and regulations can vary based on jurisdiction, so it's essential to consult with a legal professional in your area to understand any specific rights or obligations you may have in this situation.
If you have concerns or feel that your ex-husband's well-being is at risk, you may wish to encourage his current wife or family members to ensure he receives appropriate care or to raise the matter with the appropriate authorities if necessary. But again, your direct involvement in these decisions may not be legally required or expected.