My wife has sole custody of the child with all rights only to her with NO access or NO visitation right to the divorced Ex-husband. Should we still need to get this document(IMM 5604) signed from the ex husband who has NO custody or NO access or visitation right to the child?
Is this form still required in this case?
Let's start with this: do you think the ex-spouse would actually sign it?
Because obviously, this will be easier if you can get that letter.
If not: I could opine that I don't think it should be needed etc but the reality is, you probably need a lawyer.
Because:
1) The issue of parental rights is not so simple and in some countries, it may not be obvious that the person who has custody also has the right to remove the child from that jurisdiction. (No-one on this board could give a complete list of countries nor be able to comment knowledgeably without specifics about what your custodial/parental rights arrangements allow). I say this with a bit of experience as I do know of countries where
only a specific court decision or agreement removing/renouncing
all parental rights would allow this - even if the other parent is barely involved.
2) When you/your lawyer respond saying you cannot / will not provide that form, you're going to need the lawyer to make the best, succinct and coherent legal case that the parental rights you have (those your spouse does not have) also mean, unequivocally, that the custodial parent has the right to remove the child from the country without the other spouse's consent.
That said, others may know better based on country etc and possibly a letter would convince IRCC. But I'd get prepared by speaking to a lawyer.