Yeah, unfortunately my husband refuses to pay the extra almost $1k for in person as 'we're already paying thru the nose'. Well we'll see how it goes. And we're also using the savings category for ILR so wish us luck in nov 2017!
It's "only" £590 for in-person (plus an additional £75 if you want a Saturday or early or late appoinment). I don't know if that £400-ish difference would help you convince your husband.
But if you really do plan to do a postal application, please consider sharing your application date, and you can be the first on the spreadsheet. We'll start tracking this like they're doing for the other visas.

Also, on a health note, my dad had his first heart attack at the age of 42. The blockage was in the artery referred to by his cardiologist as "the widow maker", but my dad had a triple bypass and made a full recovery (my sister caused a minor kitchen fire around the same time, and my dad painted the interior of our house during his recovery from the op!). About 11 years later, he had another heart attack, and ended up needing another triple bypass. And about 10 years after
that, he had stents put in. And a few years later, he had a pacemaker fitted. It took 24 years before the heart disease finally took its toll.
Really, now that your dad has had a heart attack, he's in a safer condition than before, because now he'll be getting closer medical monitoring and he knows what to look out for.