It's very sad to lose the password.
I have a special book where I write down all the passwords. If the password is long, I print it on the printer and paste it into this book.
I have several working computers at home. In each of them there is a special folder to which all the passwords that I need are located. This is done so that if one computer crashes, then all passwords will be stored in other computers. This I did after my friend lost the password from the purse with BTC with a very large amount.
That's a very good idea.
I have kept all mine on a USB, but a notebook as additional backup is not a bad idea at all.
The paper copy saved my ass
I think I will do the same now. That's bad, does your friend have no way to open the BTC purse?