You saying she leaves has no weight. She shows that she must return with her job letter with approved leave, business, her children's school activities etc. Keep visit to 2 weeks saying she wants to meet her niece/nephew. Would leave the ceremony out as that is one day. No mention of support or help.
She has 3 refusals which is a lot. She should not apply for a few months until the baby is born. To IRCC, it looks like she is desperate to come If she reapplies right away, Then her invitation letter includes date of birth and coming to visit.
