Hello, I am Rafael. Thanks for asking your question - I'm here to support you. (Information posted here is not private or confidential but public).
I am very sorry to know about this very sad and frustrating situation.
It seems he has been in touch with your children via phone on a regular basis for this long, but has avoided letting them know something so important that should have not been kept secret from them.
Your fears and concerns are absolutely valid and fair, they show you care about your children and do not want to expose them to further pain and wounding because of their father neglect and lack of responsibiity
Should I tell the children and allow them to attend this gathering, by the way their father will not be there just his family.
I support you and believe that he must start taking real responsibility for the way his choices, passivity and actions affect your children's lives and well-being.
should I tell the children at all or should I wait for him to tell them.
I think the best approach could be for you to contact him and confront his unacceptable behavior, asking him to tell them about it, and be clear that in case he continues avoiding taking responsibility for the way he impacts your children you would have no option but to do your best to protect them from getting hurt, thus that you would have to tell them about it, but would not tolerate similar situations to happen since they do not need nor deserve that.
The more he delays telling the children about it, the more painful it would be for them, but if he refuses to be assertive, respectful and caring about your children's feelings and well-being, you would have to continue taking good care of them and tell them about it.
Children use to feel guilty about everything happening in their parents' marital relationship and life, thus tolerating or allowing any form of neglect or abuse under any justification would not help, be healthy or wise at all; it would wound them, and they do not need nor deserve that.
Thus if you choose to send them with their paternal family, please make sure they know about this situation, and even if then do not happen to go, I believe they need to know as soon as possible about it.
Does it make sense?
Yes. Thank you for your help.
You're very welocme.
You're very welcome.
Thank you for your trust.
Please feel free to contact me if you have any further question, since I am here to support you as possible.
You're welcome. Have a good day.