T8 is not bad, with that said, your friend wont yield much with that set up
T8 is ok and actually as good as T5, tho life time and drop of output over time is much better with T5`s
you have to go T5HO (HO = high output) to get high output bulbs
beside that go for the highest Watt possible and the right Kelvin (Kelvin = colors of the light)
some high wattages (56W) T8 in the right Kelvin can do ok if you have enough and train your plants and of course provide them with all the necessary stuff it normal receive outdoors in nature Etc. wind, fresh air/co2 water in the right PH and the right food/nutrient aso
a 4 foot 6-12 tube fixture with 56W in a mix of 6500K and 2700K could do ok