Surely they have some sort of duty of care when discharging patients?? The aftercare isn't their responsibility, but yes they have a duty of care, and in particular a performance indicator around premature re-admittance. So phrases like "unsafe discharge" can be handy. Be prepared to be determined to the point of bloody mindedness.
They won't look at reablement until after the op because it's not till after the op that they know what reablement is required. They can move quickly once they know what they're dealing with - be prepared for major changes with, if you're lucky, a few hours notice. The 6 weeks is a max. If they think you are coping after 3, then it'll stop, And if at any time they think you'll need continuing care, then the responsibility transfers to SS, and help will be means-tested.
I also completed something at the gp surgery that means I can talk to them about his health / medical matters. You'll need to do that separately for the hospital.
Ward advice regarding removal of stitches was “make an appointment with the nurses at your gp practice”. Not much good when they “don’t do that” (their words). It would be the district nurses who do the stitches, and they're accessed through the GP. Not the practice nurses who don't do home visits or stitches removal at the surgery. I can see how confusion can creep in.
He needs to be very clear about the things that may cause him difficulty at home, and to say that he doesn't have family who can help - elders are often reluctant to say this, because it reflects on their ability to maintain a picture-book family life. They tend to overstate the help they get from family and give totally the wrong impression.
SS Occupational therapist can order aids for home. They're on loan, so don't have to be paid for. But sometimes are slow in coming (days rather than hours). If you buy your own, you may be eligible for VAT relief - I think it's if it's a permanent need rather than a transient one, so not temporary crutches after the op, but if the op leaves him with a permanent unsteadiness requiring hand rails, for example. (Really saying this for other people reading the thread who may not know about VAT relief). But not every outlet is set up to give you the VAT relief - it's easier if you go direct to the supplier rather than, say, via Amazon.