He is better off buying a cheap standard FLA (wetcell) or AGM for this round until he figures out what type of camping he wants to do..
If he is only camping where there is commercial power all the time then Li will be a total waste of money as he wouldn't be using or taking full advantage and the cost of Li.
He also does not have to replace the current power center, there are aftermarket slide in replacement power converters which can slide right into the current WFCO power center. One can also buy deckmount converters in which you just wire those in and disconnect the power to the WFCO converter.
The slide in replacement converters tend to be a bit more cost effective than adding a external deck mount..
Typically Progressive Dynamics (PD) converters are pretty highly regarded and that is what I have and am pleased with it.