Hello Saucheaquail17
I am sorry to hear that. I wish your mom and family all the best, and that further examinations will turn out in better news, so you can return to Switzerland again.
The conditions and proceedings for cancelling saver offers are described here:
https://www.sbb.ch/en/help-and-contact/refunds-compensation/refunds-compensation/ticket-refunds.html#anchor4
You can cancel them provided you have a medical certificate from a PhD proving the unability to travel.
SBB is not offering travel insurance options with their tickets; I don’t think your local public transit operator does either; this is a private matter of each traveller, if needed.
I, personally, do not have signed a contract with a travel insurance either; however, my credit card bank is offering me such, provided 51 % of the trip costs were paid with their credit card. I am not sure if that is the case with you?
Kind regards,
Roland