Frustration

A boring picture I know but its what stopped me getting a shot in the light. Just how many different shower hoses are there that are 'universal'. I just want to help 88 year old dad with simple task without wasting money on a plumber...I have changed hoses several times on other showers...this can't be that hard.

Husband is quite right...why don't I task brothers with fixing it...bu I probably won't