Most Comfortable?

HardellI found this sentence at flo-joe: "... in a way that they feel most comfortable in.".
I'm wondering, whether there should be "the" before "most comfortable" or not.

"The" is optional in this case.

I wish you had included the whole sentence. The double-"in" seems redundant. (maybe not)

Do it in a way [that] they feel / are [more] comfortable with.
Do it in the way [that] they feel / are [the] most comfortable with.

There are other problems.
The indefinite article "a" would go with "more comfortable."
The definite article "the" would go with "most comfortable."

Do it [in] the way that makes them [feel] [the] most comfortable.

Do it in a way that makes them [feel] more comfortable.

Context could have an effect on these choices.

Your original phrase, as it stands, is not a good one. Adding "the" will not improve it.

Their (7) argument is based on research that claims (ARGUE)
workers are far more (8) productive when they have the (PRODUCT)
(9) freedom to dress in a way that they feel most (FREE)
(10) comfortable in. (COMFORT)

This is the original sentence from flo-joe, with filled gaps.
I've never heard of omitting "the" before "most" + adj before.

Trust me! I'm a native speaker!

My hands are tied, because I find "to dress in a way that they feel most comfortable in" abominable.

To me, the optional article has nothing to do with the problem.

This is most distressing. fine.
This is the most distressing situation I've ever been in! fine. ("The" may not be omitted in this case.)
Do what will make you [the] most comfortable. fine. ("The" is optional.)

No doubts about trusting you. That's why I'm writing here. Because I trust the natives here .

Thank you.

AvangiThis is most distressing. fine.

I think this is an example of the elative (rather than the superlative) and it has the meaning of

This is very distressing. (=This is a most/very distressing situation)

Ivanhrhas the meaning of This is very distressing.

I agree!

HardellNo doubts about trusting you.

Now I feel bad(ly).

Regarding the article, the difference seems to depend on the presence of a noun.
It's the noun which requires the article!
This is the most effective solution to the problem. This is the best solution. (mandatory article)

What would make you [feel] [the] most comfortable? (optional "the"; no noun)

The placement of the noun also seems to make a difference.
(a) In my opinion, this plan is [the] most beneficial. (optional)

(b) In my opinion, this is the most beneficial plan. (required)

You could argue that in example (a) "most" is the elative rather than the superlative (as Ivanhr pointed out),
but I think in this case it could be taken either way.

Avangi

HardellNo doubts about trusting you.

Now I feel bad(ly). Regarding the article, the difference seems to depend on the presence of a noun. It's the noun which requires the article!This is the most effective solution to the problem. This is the best solution. (mandatory article)What would make you [feel] [the] most comfortable? (optional "the"; no noun)The placement of the noun also seems to make a difference.(a) In my opinion, this plan is [the] most beneficial. (optional)(b) In my opinion, this is the most beneficial plan. (required)You could argue that in example (a) "most" is the elative rather than the superlative (as Ivanhr pointed out), but I think in this case it could be taken either way.

Thank you. This made it absolutely clear to me. Really, thanks.