He can invest in Bitcoin mining perhaps then. All the Bitcoin mining firms should be having very profitable results for the year.
He could if he finds a company that fits his requirements in terms of the company's balance sheet and financials. But then again, bitcoin mining companies pretty much fits the "tech" category, which again, he's not interested in because it's not in his circle of competence.
People really need to stop fantasizing about Buffett buying bitcoin because this isn't going to happen.