I believe it is a Taxus Bacatta (Yew) bonsai tree. I am not sure. My BF bought it for me in JUL for my bday and 3mos later it is brown/yellow almost leafless. I live in High Desert. Due to high heat during summer I watered twice a day on very hot days and leave on patio. Only directions we received from non english speaking man was: lots of water 2x a day leave on patio.

Doesn't look like a yew but maybe close up pictures of the foliage will help.
Depends on what species it is if you have to water it a lot. Also on the weather. If it's warm you might have to water it more when the soil gets dry.
But on most species roots don't have to be soaking wet all the time.
If it get's more than it can vaporize it can easily suffer from rootrot what will result in parts or the whole tree dying off.
Also keep your trees out of the midday sun if temperatures rise. They benefit from some shelter even trees that prefer full sun need protection.
If it is a yew they prefer shade. But we need better pictures to give you more accurate advice for this species.

It does sound like the conditions are the cause. I agree does not look like a Yew. You need to water when it is needed not to a schedule. Twice a day may be too much. There is a lot of what looks like mpss on the top, That is usually an indication of too much water. Certainly shade in the hottest part of the day will help. But do not take it into the house, that will make it worse.

Thanks Chris, I will take another pic and upload to make sure I am caring for it according to it's species

Thank you!!

Chris - Here are some new photos I took this morning. If you could ID please and let me know how to fix him. I would appreciate it