Alright, well here are his options:
1) He could lease the auto and expense it through the business as he makes the lease payments. Since this is a sole proprietorship, this would be more beneficial to him than taking a deduction on his personal tax return.
2) Since the vehicle is not over 5000lbs. he is not allowed to take the extra expense during the first year and therefore would have to capitalize the cost of the vehicle (purchase price, taxes, fees, etc.) and depreciate it for 5 years for a tax basis and as fast as he wants for financial reporting purposes (creating a deferred tax asset). However I would still recommend a lease, so he would not have to carry a liability on his books, but rather go with option 1 and just expense his costs through the P&L as he pays.
To me, judging by the vehicle, he should probably go with option 1 unless he would want to step up to the Sequoia, which I would than go with option 2 to gain the benefit of being able to expense 50% in the first year (accelerated depreciation).
Since this is for his business there is no individual tax benefit until he calculates in his income from his business into his individual filing.
Hope this helps.