Influence of criminal records of a family member on BN(O) visa application

[achtneunsechsvier]

Hello. I am from Hong Kong and I have been thinking about applying the BN(O) visa to move to the UK with my family. A problem is that, an elderly family member, who is 69, had two criminal records that caused his imprisonment in the early-80s and mid-00s, both 18 months. In the last 15 years, his record is clean. Earlier I have read that the records of serving imprisonment sentences under 4 years are irrlevant if 10 years or more have passed after finishing serving the sentence. However, I saw this today:

Criminality grounds:
Immigration Rules 9.4.1 An application for entry clearance, permission to enter or permission to stay must be refused where the applicant:
(a) has been convicted of a criminal offence in the UK or overseas for which they have received a custodial sentence of 12 months or more; or
(b) is a persistent offender who shows a particular disregard for the law; or
(c) has committed a criminal offence, or offences, which caused serious harm.

It appears to be an amendment to the immigration law in December 2020. That means he, who had originally been "qualified" for applying the visa, was disqualified due to this amendment.
Does that imply as long as the family member is applying with us, our application can only be rejected with no rooms of discretions? Not even when we apply him as a dependent family member? He is now incapable of working and living himself and the whole family will have no choice but to stay if he cannot come with us.

[achtneunsechsvier]

I would add that his last sentence was related to gambling - this offence probably does not exist in the UK law because gambling is banned in Hong Kong but is legal in the UK. I think it's very likely not relevant but I am mentioning it just in case. This first sentence was served nearly 40 years ago (possession of drugs).

[achtneunsechsvier]

Just dialed the BN(O) Cantonese hotline today. It appeared that the one answering our question wasn't aware of the new immigration rules and told us to "have a try" since the immigration health surcharge will be refunded anyway. But it isn't really worth a try if we know that the rejection rate is too high because other than visa fees and health surcharge, there are a lot of other things that we have to worry about if we decide to apply for the visa. And we are worried that it will have negative effects in the future once our visa application is rejected as an entire family unit. So I would like to know whether anyone has experienced or heard of similar cases.