A. That needs to be seen to be able to understand the underlying cause.I do not think you need to think about euthanasia at this stage.
For example, plantigrade stance (the hocks are in contact with the ground when walking resulting in a squat posture and gait) is typical of a neuropathy due to diabetes mellitus (which is treatable). Other causes can provoke squat posture, I would definitely recommend to take him to your veterinarian for a consultation.
A. this could be a sign of pain in his lower abdomen. It could be caused by a GI condition (like an obstruction or constipation) but more likely to be connected to the urinary tract (could be a urine infection or urinary blockage). These conditions are usually treatable though so take him to your vet as soon as you can, hopefully he'l be ok after treatment.
Your account has been reactivated.