The short answer is that it gets significantly worse each time, and a fifth offense on the same charge is about as far from a sympathetic position in front of a judge as you can get.
Criminal history is one of the heaviest weights in sentencing calculations across every system. Judges and prosecutors are not starting from neutral when they see someone in front of them for the fifth time on the same type of charge. The prior record tells a story about whether previous sentences, probation, diversion programs, or any other intervention actually changed the behavior. Five trips on the same thing says none of it did.
Without knowing the specific charge it is impossible to give a precise range, but the general principle holds universally. Each prior conviction ratchets up the sentencing guidelines category. A charge that might have resulted in probation on the first offense carries mandatory jail time by the third, and by the fifth you are almost certainly looking at meaningful incarceration rather than any alternative.
The mandatory minimum provisions and habitual offender statutes that exist in most jurisdictions are designed exactly for this situation. Some states have specific enhanced penalty frameworks that kick in for third or fourth time offenders on certain charges and require judges to impose longer sentences with less discretion to show leniency.
He needs an experienced defense attorney immediately, not a public defender stretched across fifty cases if it can be avoided. At this stage the quality of the legal representation and what mitigating arguments can be made are about the only variables still in play. Everything else is working against him.