Thanks for your question on Healthcare Magic.
I can understand your concern.
In my opinion, we should first rule out deep
venous thrombosis (DVT) in his case.
Uncontrolled hypertension can damage blood vessels especially lower limb vessels.
And this damaged vessels can cause thombus formation in it.
When this thombus occlud the vein, it hampers venous return from that limb.
So fluid and blood tend to accumulate in lower limb.
So possibility of DVT of left lower limb is more in his case.
So get done venous doppler study of left lower limb to confirm DVT.
Control of blood pressure is must.
If DVT is there then he may need surgical removal of
thrombus.
Hope I have solved your query. I will be happy to help you further. Wishing good health to your boyfriend. Thanks.