What is the best anabolic/testosterone boosters for 56 yr. old man?

im looking to build the perfect stack for my Dad. He is 56 years old, in great health and pretty good shape. He wants to be in better shape, build muscle, become even more active than he is... but has no energy or drive. I was thinking about getting him Re-forge for a Testosterone booster, a 'sport vitapak' and some wheybolic ext. 60 protein all from GNC. would that be a good stack or is there something better?... also should he add in fish oil?..also casein after he is set on an exercise regimen?.... any advice helps! thanks a ton!! :)