Hi Kim,
Sorry to hear of the loss of your Dad.
This was the part work series which finished a while ago.
It rather depends on what you want to do. From what I recall, it was a moderately difficult project and if you are not a modeller then not something you could really undertake yourself. Getting somebody else to complete it could be quite expensive depending on how far it has progressed. Model boat building is a time consuming hobby so to commission someone to complete it could cost a lot of money well beyond the cash value of the completed model. If you want it completed for personal reasons then only you can put a value on it but then of course it would not have been entirely built by your Dad and of course it would not be unique as there are many other people who have also built it.
It is possible that someone on here might be willing to buy it if you could post some photos, alternatively there is of course Ebay!
Hope this helps.
Colin