I think it is a good idea to do this. not just for your loved one but other family members. My dad passed away when I was very young and I wish someone had thought to do this for him.

Find somewhere quiet where you can be alone without distraction. Switch off your phone and disconnect from the world. Think about him and make some notes - who is he? Why is he special to you? What is he like? What are his interests, passions? What experiences have you shared? Try not to feel pressure, there is no rush.

Are you doing this on your own? Would you want to get other members of the family involved? They could each write a small paragraph of what they love about him, that way all the pressure is not all on you.

There are professional services which can assemble the book for you to your specifications if you want. Or you could do it yourself. Around the text, try to find small mementoes, photos, tickets, images of places you have been or his interests and hobbies. If you make a film you could slip a DVD into a pocket at the back of the book, or add in a weblink. In fact if you want the whole thing could be a website, doesn't have to be a physical book. That way people could add their own audio, video, and contribute even if they cannot physically make it to be with you. If you want you could add a link to justgiving and do something to raise money for others who have the same condition. You could have a blog about him, or he could write one about his experiences.

The most important thing is to remember you are doing this from love. There is no pressure, you don't have to do it alone or within any time frame. Just do a little each day and work towards the finished thing.

Have you spoken to him about this or are you doing it as a surprise? It is worth considering as he might want to be involved, he could do a bit talking to camera or something and help assemble it. It would distract him from his illness.