My Father Just Had Surgery (most Likely Debridement) Due To

My father just had surgery (most likely debridement) due to osteomyelitis in his calcaneous. He is now non-weight bearing with a cast/boot and he will receive antibiotics for 6-8 weeks via PICC line inserted into his arm. He was told he may not bear > 5 pounds of weight through the arm with the PICC line... this will make it exceptionally hard to walk... is this a standard precaution? Thank you.