He and his mother on a private holiday?

is it normal for his mother to ask him to go on holiday with just her and for him to think that's ok?

Noel's response

Without further information, it is hard to say. If you and he and your children, if you have any, have holidays together, and his mother just wants a short holiday with him (say a week or so), it may be entirely reasonable. Is she frail and unable to travel alone? Is there some other reason she might need someone (him) to travel with her?

If she just wants her 'little man' to herself, that is a different matter, and not what I would consider 'normal'.