Also before prescribing the cream did they check is PSA level? Its done with a blood test and has to do with his Prostate? Pretty important question.
It will take time for a cream or anything to work. Give it some time. It has to build up in his system. If it doesn't help after a couple weeks (or however long his doctor said), he might discuss some other options.
Has the doctor checked his heart health?
How's his weight? Personal question, perhaps, but more fat can equal lower testosterone too and/or a self-image problem that can affect drive.