Wharta,
If he is a solo provider and his 'billing entity' is NOT a type 2 NPI, you cannot put his individual NPI in 24J. If services are provided in his office (not a satellite office), then blocks 32 and 33 should match EXACTLY, including the NPI in 32a and 33a. What does he mean "He has a group NPI, but doesn't use it"
If he is a solo provider, but his 'billing entity' is registered as a Type 2 NPI, he MUST use the Billing Entity name and the Type 2 NPI in both 32a and 33a; the tax ID # in block 25 should match the billing entity in 33; if he has an EIN # linked to the 'group', then that is what belongs in 25. Now, when I say 'group', I do not necessarily mean more than one; Even though his name may be John Doe, MD; if he registered himself as an LLC or INC whether using his name or a business name ( ABC Family Care), you must use THAT name and NPI in 32 and 33; hope this helps!! Feel free to email me at michelle@pmbausa.com if I have confused you.