Brooke, their varying classes of CDL licenses then on top of the different types of CDL license their are like 6 to 8 (or maybe more these days) endorsements like Hazmat, doubles/triples trailers, tankers, etc....
$4400.00 seems a bit high to get training for getting CDL...
If y'all have access to a dump truck or semi and you are trying to get your CDL, all you really need to do is go to the DMV and get the manual to study for whichever type CDL he needs...he can tell them at the DMV what he is going to be driving/using/doing and they will tell him which type of CDL and/or endorsements he might need...most states will furnish a study guide/manual.....some might charge a small fee
Trying to type this as simple as possible.... But $4,400.00 is way to much, especially if y'all already have the dump truck or semi and trailer/equipment y'all will be working with....just get the study material and let DMV know what you will be doing and they will let you know what CDL type/class y'all need and any possible endorsements
1 other thing, probably going to need a DOT physical also, but that's pretty simple and easy
Hope this helps
TC