That's not how tax write offs work. Let me try this again. Let's say you and I go out to dinner, you pay but I keep the receipt. The receipt shows we ate $100 worth of bullshit. The government does not give me $100 back. The write off is for the income tax, so I end up paying income tax on $100 less because it's lowering my taxable income.
I know how write-offs work. I'm talking about him saving money by not paying the full amount for meals as he claims the tax back on his return. I also suggested that when they go out for meals with people he probably offers to pay for the full meal so he can claim tax back on the full meal and squeeze some extra money out of it, despite the other guests paying their share (as in, the full table of four couples is $400, Jack pays the bill, the couples send $100 each and he files it in his return as a $400 meal on Givemeentertainment, or whatever company CWJ/JOTG is part of as he filmed the meal). The point I'm making is that I think he records all these Jack on the go videos because he was already going to eat out, and he may as well record it and claim that he was eating out for the business.
And yes, Fatty likely had a pile of cash sitting around from selling the California house along with his pre-adpocalypse income, but that doesn't last forever especially with his medical bills, and the absurdly high food bill that family goes through. They've got another source of income(likely Tammy's parents) funding this bullshit. Don't forget the timeshares, absurd vacations, and so on as well adding to their spending.
I'm not saying it lasts forever, I'm arguing that the pre-adpocalypse money probably covered all their expenses to move to, and the cost of the house in Nashville and then some - if I remember correctly, they managed to double the price they paid for it when they sold that property. The other point I'm making is that Jack has a massive library of videos, and he'll make an above-average passive income off that alone (DSP is testament to this, we know that DSP makes a decent amount of money out of his library, and his channel gets significantly fewer views than Jack does). If you add whatever money Tammy earns from her job (from what I can see, an experienced self-employed accountant can demand in excess of $50 p/h [the average salary in Tennessee is about half of that]) then they'll have a well above average household income for Tennessee. RE: medical bills - as I explained above, we know Jack had insurance, as he had to leave the nursing home when the insurance bux ran out.
There's always this assumption that lolcows are always broke and can't manage their finances. For the most part this is true, but Jack is married to an accountant, and made it big when youtube was paying out big money, and has managed to maintain a fairly sizable notoriety since then. It's easy to laugh at Jack because he's a retard, and he is, but Tammy will almost definitely look after the money side of the business and it wouldn't shock me if she does a good job of it. We see Jack hoarding a bunch of crab, but aside from the countless Apple products, pretty much everything we see him hoard is free products he got from shitty Chinese company that wanted promos. It's worth noting, too, that a lot of his vacations are road trips or out-of-season trips to popular destinations at most a couple of states over from Tenessee - they aren't pushing the boat out, and it gives the impression, to me at least, of a couple living within their means.