Mn, hope you found some good meaty ribs. If your son really likes Texas style ribs, here goes, don't want to step on anybody's toes or offend anyone. I use salt & pepper and a little rub, that's it. Most of the BBQ places around here that do Beef ribs do it that way also. You want to taste a little seasoning in the bark, a good mild smoky flavor and be able to taste the beef. I realize different parts of the country as with people the taste vary. But if he is wanting Texas style beef ribs that's it. Pretty simple, no marinade no injecting no special jerk seasoning no rosemary or thyme.
I smoke mine at 225 for around 5 to 6 hours, I spritz every so often to keep them moist, using either apple juice or 50/50 apple cider vinegar and apple juice, some people just use water, When they are done I wrap them in foil and a couple old towels and let them sit for a while. The juice will re-distribute and you will have tender moist Texas style ribs.
Gary