Cpt PB - so glad I had finished my lunch
Micro - nasal spray, solid inhaler stick, don't fly with a head cold or sore throat if you are 'sensitive', learn to 'exercise' the openings of the Eustachion tubes in your throat (practice 'ear wiggling' until you hear the eardrums click - when you don't have a cold). None of them 'foolproof'. Check the med forum here for more on the topic. I fully endorse the warning CPB issues - frequent VS can force infection/germs into the tubes which are there purely to allow pressure equalisation. I have just finished 45 years of professional aviation having 'small' eustachion tubes (according to an RAF ENT specialist). There have been times when life has been difficult.
The primary secret is to keep the openings 'open', since like any 'soft' opening they tend to close up under positive external pressure.
The very worst is sinus blockage which is what I assume the OP's husband had on the second flight. VS does not normally help with this. The pain can be excruciating and can cause you to pass out. Repetitive cycles of 'ear problems' (and almost certainly dodgy sinus 'openings' at the same time) can cause scarring of the damaged sinus drain tissues and then they can definitely block. All good fun, yes (and VERY interesting when on your own with 10 minutes of fuel remaining....)?