[mmichaels1970]

the most likely scenario for plant with lots of healthy green foliage and not so much fruit, is too much nitrogen in the growing medium/soil additives.

Thanks for the tip. I'll let my dad know about that one. Based on what I've read, it sounds like he should probably mix some sawdust, wood chips, or some grass clippings into the soil.

[greeneyes]

Increasing the P and K might also help - it’s kinda about the ratio of N to these and of course trace minerals are important. Additions I have used are bone meal, Epsom salts, banana peels and/or crushed egg shells-sometimes a tums. The egg shells will help with calcium, but it is slow release. A blender is useful with peels and egg shells.
Best of luck to your Dad.