Halacha: Can an aging forgetful leader be replaced? | Should you allow your daughter to go out with a boy who smokes or vapes?

Should you allow your daughter to go out with a boy who smokes or vapes?
Is a smoker Possul Lei’dus?
If your father asks you to buy him a pack of cigarettes are you allowed to listen?
When a president loses his sanity does he lose his staus as a president?
Would Halacha require an aging forgetful leader to step down?
If the population loses their trust in the president (or leader) can they Halachically oust him?
When a husband loses his sanity can his wife or children take away his business?
When a father loses his sanity can his children take from his money for their wedding expenses?