Yes, when the loan is secured by their own home rather than by the business being bought. Debt secured by the investor's personal assets counts as funds at risk; debt secured by the enterprise's assets does not. The loan agreement is the document that decides which category the money falls into.
Personal security makes borrowed money count
Hypothetical example: the couple draws a substantial sum from a line of credit registered against their West Kelowna house and wires it, together with savings, into the escrow for the Idaho shop. Because the lender's recourse is against the house, the couple would lose personal assets if the business failed, which is the risk the treaty-investor rules require. The full amount counts toward the investment.
Contrast a proposal from the seller to accept a promissory note secured by the shop's lifts, diagnostic equipment and receivables: that portion would not count, because the couple's exposure is limited to the business they are buying. The file should include the loan agreement, the property title showing the charge, and the drawdown statement. The couple must also meet the other conditions independently: they are Canadian citizens, so treaty nationality is satisfied; they will own the shop outright, so they develop and direct it; and the shop's trading history addresses marginality.