The penalty range for a violation of section 23153 is defined in sections 23354 and 23356 as follows:
23554. If any person is convicted of a first violation of Section 23153, that person shall be punished by imprisonment in the state prison, or in a county jail for not less than 90 days nor more than one year, and by a fine of not less than three hundred ninety dollars ($390) nor more than one thousand dollars ($1,000). The person's privilege to operate a motor vehicle shall be suspended by the Department of Motor Vehicles pursuant to paragraph (2) of subdivision (a) of Section 13352. The court shall require the person to surrender the driver's license to the court in accordance with Section 13550.
23556. (a) (1) If the court grants probation to any person punished under Section 23554, in addition to the provisions of Section 23600 and any other terms and conditions imposed by the court, the court shall impose as a condition of probation that the person be confined in the county jail for at least five days but not more than one year and pay a fine of at least three hundred ninety dollars ($390) but not more than one thousand dollars ($1,000).
So, the absolute minimum jail time would be five days, if he is granted probation, or ninety days if not. The maximum possible sentence is confinement in state prison for 16 months, 2 years or 3 years, depending on whether the court finds mitigating or aggravating circumstances.
Sentencing in such cases is highly fact driven, the most important fact being the extent of the injuries suffered by the victim. However, since your brother was bailed out for $5000 (a relatively low bail for these types of cases), I'm guessing that this is a relatively less serious offense, that a grant of probation is ultimately likely and that any jail sentence would be closer to the five day minimum than a state prison commitment.
We are not permitted to recommend specific attorneys here on JustAnswer. His best bet would be to contact the local lawyer referral service -- they will put him in touch with someone who practices criminal defense in the area. Contact information for the Tulare County Bar Association Lawyer Referral Service is available here:http://changelabsolutions.org/tobacco-control/tenant_resource/tulare-county-bar-association-lawyer-referral-service
Good luck to your brother. If you have any other questions about this situation, please let me know.