I want to know if my brother will be arrested and sent to jail for a First time DUI or if he will be charged with just a fine.

We'll need to know a bit more about both your brother and the details of the DUI to give you a detailed answer. I can tell you that barring anything unusual about the case your brother will receive a summons in the mail, so he won't be arrested.
As far as penalties, there can be jail time attached to a first offense DUI, but it depends on how drunk he was or whether there were drugs in his system. Those facts would also impact whether he's looking at a license suspension.
His prior record, if any, needs to be factored in as well. If he has no priors, he may be eligible for ARD, which is basically a diversionary program for first-timers. He wouldn't serve a day in jail and the license suspension, if applicable, would be greatly reduced.
I would suggest that you locate a Reading-area attorney here on Avvo and call one (or more) for a consultation. Several offer free consults. You'll get better advise there than you will be posting more details on here.

I practice in Reading, PA (Berks County). I can tell you that there is a program called ARD that MAY be available to him. ARD is for first time offenders. ARD includes, among other things, highway safety classes, a drug and alcohol intake, fines, license suspension and court costs. However, if he applies and is accepted to the ARD program, and completes it successfully, then his record for this offense will be expunged and he will never have to say he was convicted of this DUI.

If this is his first criminal case, he may be eligible for a program known as ARD. Under this program, he would be placed on probation and after he completes the requirements, the charges would be dismissed and he would be entitled to have the case expunged. He should retain a criminal defense attorney to make sure his rights are protected.

Jail time, classes, a suspended license and probation are all possibilities for a first time DUI offender in PA. You can refer to the chart on the link below for a full explanation of potential penalties. Good luck.

It depends on what tier DUI he is charged with. Feel free to contact me at 610-680-7842 or www.davidmckenzielawfirm.com to discuss this matter in further detail.

If you brother was arrested for DUI he will not get away with a fine. If charged he faces the possibility of probation or prison time. For a first offense with no prior criminal record, he should explore the possibility of Accelerated Rehabilitative Disposition. You alluded to it with respect to the classes and a fine. His license suspension will depend on his .BAC level, and whether he is ultimately convicted. Remember he is innocent until proven guilty.
Your brother should retain a good DUI lawyer in Reading, PA right away. I would also be happy to provide a consultation and take this case if you are interested.

If no priors, no injiry, and no other charges he might qualify for ard which means no hail and an expungement. He will ned an attorney to apply

I agree with all the answers posted. Your brother, assuming that he has no prior criminal record/conviction, will likely qualify for the ARD program. Furthermore, he will avoid jail and any conviction in his case. There are costs associated with the ARD program, which vary depending on the county.