My husband has developed large brown water blisters on his lower legs, can they be related to his lung diseases ipf and copd?

Blisters on Legs: Blisters on the legs can be caused by:an allergic reaction, herpes simplex, infections like staph, fungal infections, drug eruptions, diabetes, contact dermatitis, an autoimmune disorder like bullous pemphigoid. Treatment depends on the cause. See your local dermatologist for a diagnosis and treatment.

It can be: People with COPD can develop pulmonary hypertension and right heart failure which manifests with leg edema. But if he has blisters he may have underlying cellulitis or venous insufficiency. Please check with your doctor.

Maybe: Both disease can enlarge the right side of the heart. This in turn can cause edema or swelling in the legs. If severe enough you can get water blisters on the front of the legs.