I agree whole hearted with these posts.
Don't sell a house to live on a boat, as illness, age, and the uncertain future of the canal system, plus the certainty of increased costs are not something to look forward to.
Keep the property, rent it out, or if your friend can afford it, keep it for storage.
Get a bank loan for a boat,to live on, or buy a cheaper smaller boat and be a hobby boater, he can still live aboard in the summer and the house in winter.
Having spent a winter aboard, one can very quickly lose your sense of humour!