My dad's friend has not called in around 3 weeks, should we be concerned? He usually calls at least once a week?

I know he was having problems with his wife and she took his kids to another country with the wife's mother. She told her husband that she was planning to leave her own mother, and the kids grandmother in the country alone while the grandmother was slowing dying and she wanted her kids to see their grandma one last time before she left the grandmother alone there. I wonder if she returned on schedule as she previously agreed to or if she decided to stay permanently in another country with the two kids to blindside her husband who she would frequently argue with and was not happy around. It's not a big red flag that he has not called in three weeks as of yet, it's possible he is avoiding us due to a new illness but I just hope everything is okay with him.

Updates
5 mo
He called today, it’s been around 3.6 weeks since we talked to him and his kids are in Canada again.
My dad's friend has not called in around 3 weeks, should we be concerned? He usually calls at least once a week?
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