He can encourage her to pursue her career goals. For instance, if she has an important project at work, he can help her manage her time better at home so she can focus on work when needed.
Help with practical things. Maybe help him organize his work schedule or do some research related to his work if she has the relevant knowledge.
The husband can stand by his wife and believe her. He should encourage her to take action against the blackmail, like going to the police.
Another way is through networking. She can introduce her husband to her own professional contacts if relevant, which might open up new opportunities for him in his career.
They can also network for each other. Attend some business events together and introduce their partners to useful contacts in their respective industries.
He can offer practical help such as helping with household chores so she has more time to focus on her work.
She can start by being understanding. For example, when he has to work late or go on business trips, she doesn't complain but offers her support. Also, she can use her own network to help him make connections. Maybe she knows someone in his industry who could offer advice or a new opportunity.
Another way is for the wife to be actively involved in his work - related social activities when appropriate. This can expand his network and show her support publicly.
A wife can contribute to her husband's career growth by being his sounding board. He can bounce ideas off her regarding work projects or career decisions. Additionally, she can encourage him to pursue further education or training opportunities that will enhance his skills. If possible, she could also help with the administrative tasks like proofreading his resume or cover letter when he's applying for a new job.
The husband can offer practical help like taking care of household chores when the wife has a big project at work. This gives her more time and energy to focus on her career. Similarly, the wife can do the same for the husband.
Help him manage family affairs better. By taking care of family matters such as taking care of children and doing housework, he can focus more on his career.