Welcome to Health Care Magic
Sorry to see his condition.
He is in advanced stage of heart failure
(bi-ventricular). In such cases, the life expectancy is a few months (at the most 2 years is the upper limit in general). The count down seems to be on already. There is no disease modifying treatment to give any hope of recovery - even a transplant is beyond question at this age. If the event precipitating the worsening could be managed successfully, he will be back to pre-admission state and pull on for some time
Sorry to say thus - but your description gives no hope
Wishing speedy recovery