This message means that one shouldn’t use a tourist visa to enter the US with the intent to adjust status, because that is a no-no
No, not everybody moves to the US by using a tourist visa to enter and then file for an adjustment of status. The ‘proper’ way to do it is to file for a K1 or CR1.
Just an FYI, I don’t know if you have siblings, but before you want to also have them enter the US on a visitor visa and file for an adjustment of status for them, that will not work.. Starting to see a pattern here.
This makes me wonder if you know what visa to apply for? You are talking about doing the adjustment of status, which is not a visa and also not an option for you. You cannot use a non-immigrant visa (or Esta) to enter the US with the intent to adjust status. The IR1 is your path, or possibly DCF.
His health is on the line here as well, protection might fail (I assume you are/will be intimate) and that puts his health at risk.
Apart from the ethical and moral aspect, you have (and will want to have) to let him know this PRIOR to getting to the US. It is not fair to keep this from him..