“... she is pushing 70”.
I am a firm believer that each spouse has something good to bring to the table but yes... in some cases, both are not great with money. To me, that is bad, bad, bad. My youngest brother, for instance, said his “I do’s” without knowing his brand new wife’s money issues. He was informed (on his honeymoon) that she still owed twenty grand for student loans and fifteen grand on her car. I won’t even get into the Visa bill! He called me to vent and I said “welcome to marriage. The wedding ceremony is OVER and now it is time for the two of you to sit down, rationally (no fighting or arguing) and come up with a good budget that can be done without either of you starving”. Fortunately, they did and have started out relatively on the same page with a plan in motion.
Dang! She must be a real looker for him not to bring up the subject of finances before he said I do.
Yes, usually one is better than the other. I am good with money, but my husband is far superior in his knowledge and analytical skills, and he does not mind doing it. Beyond fine with me for him to handle the financial duties.
In the case of my hapless sister and her husband, both are smart and either one would probably do the job, but I think it is a communication and power issue.
That is great that your son and his wife worked out their situation. One of my sons lets his wife handle all of the money issues. She does okay, and I am pretty sure they don’t have any credit card debt. IMO, she wastes an awful lot of money on dumb stuff, but it’s none of my business, so I keep my mouth shut.