Welcome to HCM,
After going through history in details,he is having multiple heath issues, Diabetes
,COPD,Deep vein thrombosis
I can understand your concern for his health,as far as I know there is no drug interaction
and Lasix, please do not worry and treating team of doctors will do what is best for the patient, have faith in treating doctors and remember every thing is not in control of doctors and humans.
Any one who has multiple problems treatment is quite challenging and we must always hope for best, good luck.