Hello
Normal heart working is up to 70% and your father's heart is working up to 50 % , this is no so bad .
However, get in
angiography and they will find out any blockage in arteries of heart ( blood supplying ) .
Thereafter take some decision , till need not to worry .
Now read this carefully , I being as physician and tried and cured many patient .
Take fresh juice of CREEPER POMPION ( GHIYA in Hindi ) 300 ml , mix 10 fresh leaves of basil ( tulsi ) + 10 black pepper .
Now drink this juice on empty stomach , don't take anything one hour before and after this juice .
in the beginning patient will fell some gurgling sound in abdomen ( may have 2-3 loose motions ) but after 4-5 days , you will notice difference .
Mind it this is my experience , so there is no any scientific proof , you can use for your father .
One thing I can assure that there will not be any harm .
Good luck.