If this man were depressed or suffering with some form of bipolar disorder, the periods of withdrawal would be longer. He is clearly just a selfish person who knows perfectly well what he is doing. I would do two things: firstly, speak with your friend and find out whether these three-day silences only occur when they are in your company. If they do then there's nothing for it but to stop going away with them and inviting them to spend time with you because you are the trigger for his behaviour. Secondly, if this behaviour is only with you, I would speak directly with him and ask what it is that makes him feel he wants to withdraw because you may be able to get around it. If on the other hand, he is like this with all the friends they have then he's just a self-centred person and he's not going to change until his wife tells him she's had enough. Either way, I don't think you should dampen your holiday and social atmosphere by having him around. By doing that you are colluding with him, allowing him to continue, giving in to his selfish ways.
Angela Rayner lashes out and calls Sunak “pint sized loser”.
Why Are Blokes Obsessed With Noisy Gadgets??