https://www.slab.org.uk/faqs/is-it-only-your-income-and-capital-we-need-to-know-about/
No.
Civil legal aid
If you have a partner or spouse then in civil cases we will usually need to know about and take into account all of their income and capital too.
The main exceptions to this are if your partner or spouse is the opponent in your case or if the relationship has ended.
If the application is by a person under 18 years or still in full-time education, we may have to take into account the income and capital of their parents or others who have accepted them into their family.
When we refer to "your" income or capital that includes the income and capital of your spouse or partner.
For a child we mean it to include any adult such as a parent whose resources have to be taken into account.
Children's legal aid
If you have a partner or spouse then in children's cases we will usually need to know about and take into account all of their income and capital too.
The main exceptions to this are if your partner or spouse have a contrary interest in the outcome of the case or if the relationship has ended.
Criminal legal aid
We need to know about your partner or spouse's income if their disposable income is over £222 a week. The only exception to this is if they have a contrary interest in your case. This is when they are the complainer, co-accused or are a Crown witness.