1. How this job vacancy came up? Was someone let go? Then he should think twice to take this job because this indicated unstable job security.
2. Are there similar jobs or companies that may hire him if this job does not work out?
3. Are there jobs for you nearby, with 15 miles distance? You are going to stay home and two income become one right away.
If any of the above questions can't be answered definitely. He should not come.
It is a critical age at 45. If everything works out well, there is no problem. But, if it does not work well, he is already too old in California. If he hops on two jobs more later, he may be too old for companies even to hire him. Even if he can always find a job, the psychological impact is huge for him. He will never be the same person anymore, and your relationship can be ruined. Not everybody from Canada has the broad enough background to fit American job market. I think you noticed somebody complained her husband for changing jobs in 5 years. Anyone can get into that here, but not everyone can get out that without a strong heart. Think all pros and cons thoroughly. I don't think it is a good idea to come.