"I'm curious if this really is a 'trust'."

Could be a Grantor Trust.

@TRPTori  Is your client's SSN on the 1099? Or is it an EIN?

For trusts, you should always obtain the Trust Document and read it to determine what you are dealing with.

"I filled out the sch D, as well as filling out the 8949 adding in the short and long term, including the investment fees as I was taught."

Investment fees cannot reduce the Capital Gains. IRS threw that out years ago. They are a 2% of AGI miscellaneous itemized deduction, which is not an allowable itemized deduction currently.