This link says Liam was a social work student. They went to celebrate his Mum's birthday and it was for a week
I don't know about family dynamics etc. or exactly who did and didn't go
'Mcphee had last seen her husband on March 14, when he departed their Dundee, Scotland, home to meet his family in Glasgow before they boarded the cruise in Southampton the following day, she said. The family was taking the cruise to celebrate Jones' mother's birthday.'
He travelled from where he lived in Dundee with his wife, to where his family lives in Glasgow so they could set off to Southampton together the day/night before the cruise the following day. I'm assuming they drove from Glasgow to Southampton which is around an 8 hour drive non-stop, from Scotland all the way to the south coast of England. I don't know how many cars went (if they did drive down that is), maybe the car was full or cramped with people and luggage. Then a week-long, or 'several days' long cruise, depending on your news source, stopping in Denmark, Norway, Germany and Amsterdam, then back to Southampton. Then the drive (?) back to Glasgow and Dundee. Personally, it's not my idea of fun, I'd find all the travel and cramped space too much. Cruises aren't my thing either. This is obviously just how I feel, my own opinion. It could also be that some of the family and partner aren't overly fond of each other and just avoid anything other than polite company every now and then. I have absolutely nothing to suggest that's the case by the way, I have no idea how they do or don't get along, just voicing my thoughts. They could also be really comfortable and open with each other, enough to say no I don't fancy it, have a great time though
MOO