Getting to Asia by boat

A friend's elderly father wants to come out to Laos to visit her but can't (or won't) travel by train. He loves boats and would love to get as close as possible by boat - he won't be able to and wouldn't want to work his passage but also doesn't really need the full luxury package. Is there anything in between, does anyone know? So he can come here by boat but without the journey turning into a major expense?????

Where are you coming from?

Oh yes - that would help! He'll be coming from the UK but could do a chunk of the journey by train - though he probably wouldn't be up to the Trans Siberian railway.

Any advice or thoughts would be wonderful.