Don't base your decisions on pay as it is literally impossible to predict your husband's potential path. I am of the belief that pilots at heart, will always find a way to fly because that's who they are. To those who are just casually intrigued to pilot an aircraft but don't do well tolerating the professional pilot lifestyle, it is prabably not a career choice that I would endorse. The stability and predictability of an airline career is very difficult to draw a bead on and has the potential to destroy relationships and finances if not managed carefully. The old saying is that becoming an airline pilot will either make a strong relationship stronger, or quickly finish off a weak one.
I am one of the guys (and there are many here on JC) that was born, and maybe pre-ordained in a prior life to fly airplanes. As the doctor pulled me out, I was looking for an airplane and the keys that would make it fly. It's part of our DNA and if you were to draw blood on any of us, I'm pretty certain that part of it would show up as jet fuel. It's just who we are and we never considered being someone or something else.
The age issue? I read a story about a 60 year old lady starting law school. She was asked why, at her age, she would ever consider such a thing? She explained that she had always wanted to be an attorney. If she starts today, in three or four years, she's a 64 or 65 year old attorney and is happy. If she talks herself out of it and listens to all the nay-sayers, she will still be 64 or 65 in a few years and not be an attorney and likely have regrets. Time doesn't stop, but dreams unfortunately run out of steam all too often.
Are you and your husband dreamers? Will your husband be happy NOT being a pilot? Will you embrace and support his efforts? Will your husband look up at a passing jet and always wonder what could of been that now isn't? Those are the keys to your puzzle, not how much you will make or how soon he will be a captain. Those things the Universe gets to decide.
If it makes emotional sense and it feels right to both of you, do it. You will likely be hard pressed to sell the idea (even to yourself) if it is based on any sort of logic or common sense. Don't fight being who you are, but don't try to become someone or something that you are not. Hope that helps...
Good luck.