He can be feeling extremely tired and lethargic due to the effects of the depression
and medicines. If I was your brothers treating physician, I will do the following:
1. Adjust the dose of Lipitor
or change the medicine because it causes muscle fatigue
as a side effect or add a supplement to cover that.
2. Change the antidepressant to a better activating one that suits the cardiac patients, adjust the antidepressant dose or make a combination.