Did he telephone BATF within 48 hours of discovering the theft and then submit a written report to BATF on BATF Form 3310.11? Did he report the theft to local law enforcement authorities and obtain a case number? Did he make the appropriate entries to his "bound book"? He was required by 27CFR 478.39a to take these actions. If he complied, he should have had no problems with BATF. If he didn't or was late in reporting, that may have been the source of his troubles.
Yes jumped through all the hoops and they did not fine him or anything like that. His insurance finally paid off on the stolen guns but it was quite a hassle and he said it wasn't worth it happening again.