Hi. Thanks for your query. The history of Stroke, Heart attack and Pacemaker indicates that your Father must be taking some medicines for thinning blood. This may be the reason for blood in the urine. Immediately get the coagulation profile done and consult a Doctor to get the other investigations and treatment to be done.The stomach pains can be due to constipation itself. Miralax should have helped. You can try enema, and if still has pains as he is already not taking anything orally, it is better to get an opinion of a Doctor to see and examine the abdomen. Get the following investigations: X-ray of the abdomen in standing position. Ultrasonography. Urine : routine, microscopy, culture and sensitivity - get whether there is a bleeding .