If I die first... Widow Notebook

My wife has no notebook. She uses an iPad. So where does she plug in the tails usb-drive? She cannot plug it in my notebook because the BIOS is password protected and boots only the internal drive with QubesOS. I’ve already bought a small notebook that does not use too much space in the vault. Now I’m looking for a secure OS with no unneccessary software on it and a simple GUI. With “secure” I mean noone can access the files without the password for fde (luks). I hope Luks is secure…