I would favor Chavez by decision as Chavez has shown he can beat elite boxer/punchers. Saying he would stop Prograis, I would doubt it. All things shown thus far in his career show Prograis being a real tough nut.
I may be being a little controversial here but I think Chavez sr is too old. I'll go with Prograis for this one.
I don't know. With this new crop of fighters. I see Prograis aging Chavez a few more years. You know....wait until Chavez slows a bit.