I read your question and I understand your concern. What I think is the most probable diagnosis which I think your doctors are also suspecting is a thrombosis of the deep veins in that limb. That is a possible complication in patients confined due to paralysis due to slower circulation in the paralyzed limb (no muscles contraction to help pump the blood). It is a dangerous complication because it could be also release blood clots in circulation and cause pulmonary embolism (infarction). So if the ultrasound confirms that diagnosis he will be probably put into treatment with blood thinning products for many months. It is unfortunate since he has repeated bleeds in the brain and blood thinning products might increase the risk of that happening again (depending of course on the cause of those bleeds), so it s not a perfect solution but it s about addressing the issue with the higher percentage of risk at the moment. I hope things work out for the best.