He's probably not a actual Trooper, rather he's a solicitor raising money for an alleged charity which is really lining someone's pockets (maybe his) instead of helping anyone else. Do not answer unknown calls and do not call them back. Consider getting a call blocking device for your parents (or app for your cell phone)-they're available online and start around $45. http://800notes.com/nb/search?q=call+blockers

Listed as # 7 on the 50 worst charities http://www.tampabay.com/americas-worst-charities/worst-charities.pdf  you find  "International Union Of Police Associations, Afl-Cio, Sarasota, FL"  Also Soliciting as:
Florida Police And Troopers Association
Florida Police Officers Foundation
National Patrolmen'S Foundation
Using their predatory Solicitors:
Courtesy Call, Inc. -- Las Vegas, Nv
Donor Relations, Llc -- Wilmington, De
Jak Productions, Inc -- Atlanta, Ga
Outreach Calling -- Reno, Nv
https://csapp.800helpfla.com/CSPublicApp/GiftGiversQuery/GiftGiversQuery.aspx
Florida also allows compliance under the FTC's TSR do not call laws see https://www.fldnc.com/About.aspx Effective July 1, 2013

This # calls me multiple times a day but no message

I have been getting phone calls  several times a day even on Saturdays and Sundays! Never leaves a message

I have been getting phone calls  several times a day even on Saturdays and Sundays! Never leaves a message