Honey, you're not going to get a 5 - 10 year term policy on a guy who's 73. You're going to be buying a "guaranteed issue" whole life policy. And you're not going to find that much coverage, even if you "stack" them up.
Mutual of Omaha, and Globe Life both have policies like this. Premiums are what they are, at his age. And the CATCH to the no medical exam policies, is that you have to live at least two years after you start paying your monthly premium, to collect the payout.
So. Here's some of the rate info from the Mutual of Omaha site:
Policy limit $5,000 to $20,000
Policy annual fee $12
Rate varies by state, but when I checked for my 71 year old mother in law (who, being female, would have a lower rate than your father), it was around $75 a month for $5,000 of coverage.
Do the math. 75 x 12 x 2 = $1824 paid in - IF he lives two years, which is long enough to collect. And if he lives two years, he'd probably live at least five years, which would be $4560 paid in. For her. For him, it's likely going to be over $5,000. Which means, if he lives longer than five years, you're better off just putting the money in the bank. And if he lives less than two years, you're better off putting the money in the bank.
You're getting not very good odds, that he'll die between two and five years from now.
So the ONLY product you are likely to buy - assuming you don't want a single payment, paid up life insurance policy shelling out about $30,000 right up front - is really a waste of time . . . for both of you.