Could a ankle boot help heal torn/pulled tendons or ligaments? it's been four months but won't heal. little things like bending down/stairs reinjure

It is possible.: HAve you been followed by an orthopedic surgeon for your problems. If they have not healed I would consult a specialist. Consider physical therapy as an alternative. if all conservative therapies fail you may be a candidate for surgery.

Not: If you have used it this long and not helping, I would see an orthopedist

Need to get checked: It sounds like you need some physical therapy for your ankle. And actually, wearing a boot or protective device for too long can lead to the muscles/ joints actually getting weaker. Please see your doc for this.