the sentence should be complete in the following way " Mi mamá es paciente". This would mean my mother is patient" In the case of "cuatro" (4), it makes reference to a number so you can say " tengo cuatro hermanos".
"Gris" is a colour. an example could be " Mi libro es gris" and "moradas" is another colour but in the plural form. " Estas frutas son moradas".
