He’s disabled. Permanently. He is on permanent medical leave.
Does this mean he has a medical retirement pension from his place of work? Or he had/also had, an insurance policy that kicked in when he became unable to work and provides a monthly wage based on what he earned when he worked? The T&Cs will state the rules for those.
If he doesn't have either of those and is on benefits, then that has different rules.
He can only have a limited amount of cash in the bank. So I’m going to be the breadwinner out of necessity.
I don't understand what you mean by this? Why can he only have a limited amount of cash in the bank?
If you are talking about welfare benefits, that depends which benefits he is on.
e.g. the disability payment for adults is PIP. PIP is an in work benefit, therefore it is not affected by the claimants earnings or capital.
Contribution based benefits are not affected by any savings or capital of the claimant or their partner.
Means tested benefits are of course affected by capital but in some cases that only reduces the benefit amount paid by a small amount for every £500 they have over 6k and below 16k - it depends on which benefit it is.
He will know all of this.
When you move in with your partner, he also knows that he must inform the agency of every benefit he claims, that his circumstances have changed. He is not allowed to claim benefits as a single person when he is not.
https://www.gov.uk/report-benefits-change-circumstancesThe main thing you will have to be very careful of is to ensure he does not take any Public Funds for you as an extra payment on his benefit claims, as that would be a breach of your No Recourse to Public Funds visa condtions to be in the UK. It's the visa holders responsibilty to ensure they don't take public funds. The benefit agencies will not tell you it is public funds. Charities recommend that a specailist benefit immigration advisor is consulted before claiming any public funds when one partner can take public funds and the other must not.
https://www.turn2us.org.uk/Benefit-guides/Nationals-of-non-European-Economic-Area-(EEA)-coun/My-partner-is-a-person-subject-to-immigration-cont