Hello.You had originally asked for my assistance, but I was away from the computer. But I notice that the question is still open.
While I agree with most of what was said by the other expert, there is some clarification that would alter the recommendation. Yes, new onset of significant weakness is a worrisome sign. However, you do not say whether the weakness is new since he left the hospital. If he was discharged with weakness, that usually indicates that the doctor thinks that he wil regain his strength as he recuperates at home. If his weakness today is no worse than when he was discharged, it is not as worrisome a symptom, and there would be less need to be seen quickly.
A lack of a bowel movement is usually not serious, but it can be a sign of a more serious underlying condition of the gut, such as an ileus or an obstruction, which also can be due to the impaction mentioned by the other expert. However, when these problems are getting serious, there are usually other symptoms present, such a nausea, vomiting, or significant abdominal pain. New onset of weakness also would be a concern, but it would be less of a concern if his weakness is not significantly different than the day he was discharged.
Is there any additional information that would be helpful?