Google Chrome app is outdated, and it’s not Ledger’s fault that Chrome decided to remove apps from the browser, so they nedd to made other solution. Ledger Live is not perfect, but still it is better than old Chrome app. Windows 7 has come to the end of its path, at least as far as official updates are concerned. I too used the W7 almost until the last day, but for safety's sake I no longer want to push something that is becoming old technology.
You should not upgrade firmware on W7, Ledger does not officially support this operating system and everything you do you do at your own risk. Upgrade on W10 takes just few minutes, but you are just swim against the water current, it's not easy and you're just making trouble for yourself.
No need for this, each manufacturer clearly states what are the minimum conditions for using their devices. Firmware is something which is necessary to make from time to time, how otherwise eliminate all vulnerabilities and add some new features, and improve security?
Basically Ledger devices may still work with old Chrome app, but last time I checked I can only use app that I have installed since before, and Ledger Manager was completely unusable without the ability to add and remove apps.
My advice to you and your friends is to update W7 to W10 for free, there is no need to format disc or anything like that, you can keep all programs and files intact.