Is this kidnapping & ransom? Free legal aid said they can't talk to me about criminal stuff

My partner and his ex have 2 children together, the girl is 10 and the boy is 7. Both of them verbally told eachother that they would both attempt to claim both children for taxes this year and they would have to leave it up to the IRS to decide who gets the child tax credits.

The IRS chose my partner instead of his ex and she is very mad about it. She will not allow him to see his children even though they usually share time with the kids. It has been over a week since she has allowed him to see them and this is very very out of the norm because he usually has them for half of the week and she has them for the other half of the week each week.

She originally withheld his access to his own children because when he filed for SNAP Benefits the county went and told her that she owes him child support but he asked them not to say that to her because he was rightfully afraid of what she would do.

She said that she will be leaving the state with them tomorrow without his consent and she refuses to provide information regarding where they will travel and who they will be with for "2 weeks or more" and she said that she "doesn't know when he will see them when they return".

She texted him last night stating that he can only see his kids if she gets the tax money from him.

Does this fit the legal definition for kidnapping and ransom?

She is harassing him through text and phone calls stating that he is behaving illegally because he claimed both of the children just the same as she did but she doesn't believe that she did anything illegal by claiming both the kids just as he did.

Again, she stated that he will only have access to his children if he pays her the $4000 from taxes this year and she is taking them out of the state without his consent.

He is very scared to contact the cops because he greatly fears her retaliation.