Currently, an individual is barred from sponsoring a member of the family class where the individual has been convicted of an offense of a sexual nature against anyone, or of an offense that results in “bodily harm” against a specific member of their family. For the purposes of an offence that result in bodily harm, the listed family relationships include:
a relative (related by blood or adoption) or family member (spouse, common-law partner, dependent child, dependent child of a dependent child) or conjugal partner of the sponsor; and
a relative or family member of the sponsor’s spouse, common-law or conjugal partner.
The sponsorship bar is in effect until the individual is either pardoned or acquitted, or where five years has elapsed since the completion of an imposed sentence.
Under the proposed changes, anyone who has been convicted of an indictable offense involving the use of violence punishable by a maximum term of imprisonment of at least 10 years or an attempt to commit such an offense will be barred from sponsorship.
As well, for the purpose of an offense that results in bodily harm, the listed family relationships will be expanded to include:
former family members of the sponsor;
former family members of a family member or conjugal partner of the sponsor;
current and former family members of a relative of the sponsor or the sponsor’s family member;
former conjugal partner of the sponsor, as well as current and former family members of the conjugal partner’s relatives;
a child under the current or former care and control of the sponsor, their current or former family member, or conjugal partner;
a child under the current or former care and control of a relative of the sponsor or a current or former family member of that relative; and
someone with whom the sponsor dates or has dated, whether or not they live together, or a family member of that person.
If his charges were from 15 years ago, 5 years should have lapsed since completing his sentence so he would not be barred from sponsoring you. Even though there is the 5 year rule, there are other issues at law such as who the offense was committed against (was it a member of the family listed above) and if the charge was brought by indictment. I suggest speaking with a lawyer since sexual offenses are really complicated issues when dealing with Immigration.
He could get a pardon, but that's 10-12 months of waiting and again, there are issues since it was a sexual offense and depending on the extent of it, there might be additional waiting times to even begin the process. If he applies for a Pardon, they will supply a letter to your husband (at his request) for Immigration purposes to explain that a Pardon is in process.