Perez served as pastor at St. William from 2002-2009.
Ron Pleis and his wife, Christine, have been parishioners for 25 years.
"It's really humbling for me to know that I'm going to sit here and watch this happen and watch this take place," said Ron Pleis.
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Pleis will take a bus with the rest of the parish Tuesday to watch the installation in person.
Deacon Bill Moser and his wife Donna have been parishioners here for 30 years.
Moser became a deacon six years ago and remembers how Nelson was able to keep the parish going even when many in the congregation were moving to the suburbs and the school closed.
Nelson reached out to new people in the neighborhood, some who were not even Catholic and urged them to join. In turn, it diversified the parish.
It's something Moser said continues today.
"l love to this day giving out communion at Mass. Doesn't matter if it is an English speaking Mass, all the faces are different, it's wonderful. It doesn't matter what the church should be, you could say then-Monsignor Perez was the guy who lit the fire for that."