Your friend can do 2 things about the warrant. The first is to call the court clerk where the ticket was issued and ask if there is a bond, how much it is and where she can post it (usually the local police station or sheriff department), and how much is it. If there is a bond, your friend can post the bond and get a court date for the offense. Once that court date comes, then she will have to deal with the jail time issue.
Her second option is to call a lawyer, depending on the jurisdiction, that lawyer may be able to get the warrant set aside without posting a bond. Without doing either of these things, your friend will have a warrant out for her arrest until she gets picked up by law enforcement.
I don't know that jail time will even be an issue in this case. If you have a lawyer negotiate a plea agreement, jail can usually be avoided. Pleas are always helped in DWS cases if the person gets reinstated before court and your friend needs to do this as soon as possible, whether or not he/she hires a lawyer.
If your friend cannot afford a lawyer, she needs to ask about eligibility for a public defender or legal aid.
These are just my opinions and your friend should consult an attorney about her specific case.
Jail time on an outstanding warrant is served until you either post bond or see a judge. The judge can sentence you (you then serve the sentence) or lower your bond to something you can post. Generally speaking, the court's willingness to quash a warrant or lower a bond is related to how many times she has missed court before and how quickly she addresses the information after learning of the warrant.
Either way, it does not relate to a sentence in the case other then she will earn credit toward any type of jail sentence she may receive. How much that will be is hard to say from the information available because it generally depends on her history (does she have any priors and how many) and the reason for the suspension.
Please understand that answering this doesn’t create an attorney/client relationship between us, and as hard as I try to answer your question well, it isn’t legal advice. No matter how much information you put into a question, the answers you are going to get are still going to be vague. It is in your interest to contact a lawyer, most of whom will do a free consultation. Even 15 minutes with a lawyer is going to produce a more specific answer to your problem.