It appears that your husband is applying for an annulment.
The Catholic Church teaches that consent makes marriage. Therefore when a couple exchanges consent to enter into a life long, life giving, faithful marriage it is presumed valid. When both spouses are baptized it is considered a sacrament and that means no earthly power can dissolve the marriage bond.
However, there could be a situation where one of the two parties to the marriage was unable to properly give consent at the time of the marriage and thus the exchange of consent would be invalid. This could be because one of the parties lacked maturity to truly appreciate the commitment, had an addiction that affected their consent, deceived the other party, or didn’t really intend one of the essentials of marriage (e.g. never intended to have children).
The annulment investigation looks into whether there was valid consent at the time of the marriage. It requires witnesses, testimony, and evidence regarding the frame of mind of one or both of the spouses. A Church tribunal then makes a decision whether there is enough evidence to prove one of the parties lacked proper consent at the time of marriage.
The process will inquire about the baptismal history of both spouses. Whether they were baptized Catholic or non-Catholic and, if baptized non-Catholic whether they became a Catholic later on. It sounds like the process is just in its beginning phase. At some point you will be contacted and asked if you would like to testify or offer anything to the Tribunal.
