You can offer your friends the option to use Signal for messaging. It's not a big deal to use several apps for messaging different people.
I don't know how old you are or were you live, but it just sounds crazy to me your parents want to know your location at all time, it seems paranoid. Maybe there are other "location sharing" apps out there, but they are by definition not very privacy oriented, not sure if I would trust another app more than Google-Maps...