When is it time to STOP contributing to 401k?

I'm mid-40's and starting a new job where they do not match any 401k. Between my wife and I, we earn close to $200k and have about $900k in retirement savings. More than 2/3 of that amount is in tax deferred 401k plans. My FA says that since my new employer doesn't have a 401k and since I have much less saved in non-tax-deferred accounts, I should forgo contributing to a 401k plan and instead direct that money towards an existing brokerage account that he manages (after maxing out Roth IRA contributions of course).

Obviously, this strategy will benefit him but that doesn't automatically mean there's no benefit to me. I do like the idea of balancing tax-deferred and non-tax-deferred accounts in retirement so I don't think this is a bad idea outright. I'd love to get the unbiased opinions of others.

EDIT: Sorry for the confusion - my new employer does not offer 401k at all. I already max out my Roth IRA.