welcome to hcm forum
as oer your history your husband had tendoachilles tendon injury
which was treated surgical. i would like to know how was he immbolised after the surgery. whether he had any cast or slab in his leg, whether he was walking after the surgery, whether he was weight bearing with the leg, if plaster was there when was the plaster removed,
i would like to say that you meet an orthopaedics who can examine him and find the curent status of the tendoachilles tendon whether it is intact or torn. he may advised you for mri
which will pinpoint exactly what is the status of the tendon.
the area where you had injury is got poor healing. most probably you are keeping the leg down for long time which may leading the odema of the leg and inturn leading to poor healing of the wound.
meet the orthopeadics we will ruleout any infection over there or the bleeding oozing may because of the fresh injury. yes he should go to ER for furthur management
wish him early recovery