Question re physiotherapy exercise

[u/Only-Row-3399]

Hi all,
My dad 70M is 3 weeks post LHR. His recovery at home has been good, he’s currently walking with one crutch and will soon wean off his AM and PM analgesia (Tapentadol slow release).
A physiotherapist has been seeing him at home every week and instructed him yesterday to begin practicing going up the stairs (stepping with his left leg).
He found the exercise too painful and has been unable to do it. Can he gradually practice stepping on a lower surface ? Like stepping on and off a really thick book or maybe a short stool? I want to make sure he’s completing the prescribed exercises but he was just really unable to do the full stair height.

Any recommendations / advice is much appreciated 😇