I don't know how much $ he's sending, but when I give money, I don't really want to hear that you're putting it in the savings account--most of the time.
My ILs' family give envelopes of money to kids at holidays, and almost every one of them has mentioned that their kids saved that money, so I'm pretty sure that's what they expect of our kids. So the mention savings most of the time in their thank-you notes.
But for a grown person, if I give them cash, I'm kind of hoping they'll do something more interesting than that. It's theirs to do with what they want, but given my own gift-giving wishes, I've been known to "spend" the money on something I was going to buy anyway with my own money, and then I put my "own money" in the savings account instead.
Bcs, money is fungible, and I can put the check in the savings account and spend my own literal money. It's just that for the purposes of making the thank-you note interesting, I label the thing I buy as being "from them."
Or, if I hear that the money's going into the savings account, I'd like to feel I'm contributing to something specific.
That's just a quirk of mine--hearing the money just went into the savings account, and nothing else, makes me feel a little dismissed. "Oh, we'll just put it out of sight, out of mind, in the savings account." Just my own odd little reaction.
I wouldn't mention the replacement check, and just thank him. Though, if you think your reputation