Remove all records of a person

I have a process model that runs 31 queries against our database to remove a person’s information.  This works great for 29 out of 31 tables.  The last 2 tables are related 1 contains the persons basic information the other contains 1 or more associations for that person.  The last table has a foreign key.  My process model runs without any errors but when I check the tables the last 2 tables still contain the data.

What is the best way to remove the data without removing the foreign key constraint since this is required for data integrity?

Here is the output from running the show create table command agains the child table:

CREATE TABLE `mtrperson_primarybrands` (
 `mtrprsn_primrybrnds_persnid` int(11) NOT NULL,
 `primarybrands` varchar(255) DEFAULT NULL,
 `mtrperson_primarybrands_idx` int(11) NOT NULL,
 PRIMARY KEY (`mtrprsn_primrybrnds_persnid`,`mtrperson_primarybrands_idx`),
 KEY `FK9E2AC30FB7856593` (`mtrprsn_primrybrnds_persnid`),
 CONSTRAINT `FK9E2AC30FB7856593` FOREIGN KEY (`mtrprsn_primrybrnds_persnid`) REFERENCES `mtrperson` (`personid`)

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