Final answer:
Jarrett regretted using his daughter's illness as an excuse to not continue his education, which conflicted with the example he wished to set for his daughter. Realizing this, he re-enrolled in classes.
Step-by-step explanation:
From the information provided, it seems there is a bit of confusion. The student in question asked, "What does Miles's dad (Jeff) regret?" However, the reference information provided talks about Jarrett, not Miles or Jeff. If the intent is to inquire about Jarrett's regret, then we can extract from the provided context that Jarrett's regret is using his daughter's illness as an excuse to not continue his own education.
He realizes he is not setting the good example he wanted to set for her when she challenges his lack of 'homework' by not wanting to do her own. This realization prompted him to re-enroll in his classes, demonstrating his commitment to both his education and being a role model for his daughter.