No, depreciation makes the debt more expensive as the dollars are worth more. Inflation is what makes the debt cheaper, although .gov now sells some bonds indexed to inflation.
Imagine you bought a 45K house in the early 70’s. After the Carter years of 10-15% inflation you were paying back dimes on the dollar in the 80’s.
I didn't say "depreciation".... I said "de-valuing" the currency... which, is essentially the same thing as inflation. It's just the slow, painful process of making each dollar worth less and less. Well, we HOPE it's "slow"... sometimes, the market decides it should be swift indeed.