Wallpapers like that are very common in French painting of that period and many aspects that belong to aesthetics or iconography field is not taken into consideration.
When I did read "Letters to Theo" for the first time the opposite happened to me. I was amazed by all the happiness and passion he has for his work, the admiration he has for some painters and writers, his culture, and the joy he claims painting is for him: "Painting is such a joy for me."
I realized that I should look at these paintings forgetting all I knew about his biography and for the first time I was able to really see his work and the joy he expressed in every brush stroke.
I am not claiming his health was perfect but seeing his oeuvre only in the lights of a disease is not productive and covers many of the uniqueness of Vincent's work. Even when he portrays himself with the ear cut there is an easel and a painting hanging on the wall at the background and he does not look desperate.
There are other painters and writers who were not that healthy and nobody even knows about it.
I found this site where there is the English version of the letters and I hope you enjoy it the same way I did. It's from the Van Gogh Museum in Amsterdam that I visited some years ago and didn't want to leave.
This is the link.
[Letterhead: Goupil Paris]
Paris, 15 July 1875
My dear Theo,
Uncle Vincent was here again, we were together quite a lot and talked about one thing and another. I asked him whether he thought there would be an opportunity to get you here, into the Paris branch. At first he wouldn’t hear of it, and said it was much better that you stay in The Hague; but I kept insisting, and you can be sure that he’ll bear it in mind.
When he comes to The Hague he’ll probably talk to you; stay calm and let him have his say; it won’t do you any harm, and later on you’ll probably need him now and again. You shouldn’t talk about me if it’s not the right moment.
He’s terribly clever, when I was here last winter1 one of the things he said to me was ‘perhaps I know nothing of supernatural things, but of natural things I know everything’. I’m not sure whether those were his exact words, but that was the gist of it. 1r:2
Sainte-Beuve said, ‘There is in most men a poet who died young, whom the man survived’3 and Musset, ‘know that in us there is often a sleeping poet, ever young and alive’.4 I believe that the former is true of Uncle Vincent. So you know who it is you’re dealing with, and so be warned.
Don’t hesitate to ask him openly to have you sent here or to London.
I thank you for your letter of this morning, and for the verse by Rückert. Do you have his poems? I’d like to know more of them. When there’s an opportunity I’ll send you a French Bible and L’imitation de Jesus Christ.5 This was probably the favourite book of that woman whom P. de Champaigne painted;6 in the Louvre there’s a portrait, also by P. de C., of her daughter, a nun; she has L’imitation lying on a chair next to her.7
Pa once wrote to me: ‘you know that the same lips that uttered “be harmless as doves” also immediately added “and wise as serpents”’.8 You should bear 1v:3 that in mind as well, and believe me to be ever
Your loving brother
Vincent