The below from appears to state one may be able to change one's plan.
Health Gov Site
Since the 2019 Open Enrollment Period is over, you can now enroll in
or change a Health Insurance Marketplace plan only if you have a life
event that qualifies you for a Special Enrollment Period.
Also this from law site regarding Marketplace
§ 155.420 Special ...
The rules regarding interest on security deposits are a state or even local set of laws.
For example for New York State:
Landlords of buildings with six or more apartments must put all
security deposits in New York bank accounts earning interest at the
prevailing rate. Each tenant must be informed in writing of the bank’s
name and address and the ...
Pershing is a respected custodian and there are no concerns about Pershing taking/misappropriating your grandfather's money.
However, the advisor and the broker could withdraw money from your grandfather's account if he signed paperwork authorizing them to do so. The only way to be certain is to review copies of the documents your GF signed when opening ...