he may not have a choice...going digital often means tiling together multiple prints. It's done all the time...scotchprint is one material that's digital output and is used to make billboards, the graphics on the sides of the buses and big tradeshow stuff to name a few. This is done by tiling together smaller sections and from a viewing distance looks good. The files are set up to output as tiles. they can make banners as tall as buildings, huge stuff. We made a small billboard out of this material several years ago, and used a file that was created from a bunch of 4x5 color transp. To deal with signage ordinances within city limits-- the material was stretched over this big frame above the street. It stayed up for about 3 years and weatherered very well. There were smaller ones made, that were wrapped to aluminum, if I remember right, and these looked about as good as day one after a few years as well. We use inkjets on vinyl for banners outside our building too, and they're about 20 feet long, but narrow. The problem is in the width though, as 50 some odd inches is about the max on alot of wide format inkjets. So, a 5x6 foot print might very well be 2 pieces regardless of how you do it....fwiw, we made a last minute mural on about 30 polymax II RC 20x24 sheets all tiled together of one shot that was projected horizontally onto a wall....we did another one at the same time, out of about 5 strips of 5 foot by 20 inch Kodabrome RC and pieced that together too. Fed each strip into a 20 inch processor--one part going in while the other came out....in the old days here, they used Kodak mural paper and handprocessed them in 2 huge sinks (5x9 Kreonite) using about 25 gallons or more of dektol and fix. They took the wet print, after washing, and mounted it with wheat paste to a sheet of plywood, smoothed it out and then wrappped the corners & tacked them onto the back of the wood. They dried tight as a drum...when I started here, they were just getting out of that, but we made 2 on RC paper and had to use a bunch of cans of spray mount in a spray booth to mount them....one was in 3 pieces, and we mounted it to gatorboard and then took an orbital saw (it was a vintage photo of a fire engine--hook & ladder truck) and did a profile cut around the whole thing, to make a freestanding shot. We shot a dalmatian on 120 XP1 and blew this up into a 1:1 shot and did the same thing with that....about a year or two ago, we did another exhibit with about a half dozen murals in it. One we had a shot of a building front, that was made in 2 pieces, and we made 2 sets of these. Each set was mounted onto Sintra, but one was about 10% larger in size. Our designer on that one , did a profile cut on it with a rotozip, and then mounted this over the top of the other set, so from head-on it gave it this 3-D effect.....there's another exhibit up right now, that has a bunch of 20x24s and 16x20s I made of old civil war era portraits of soldiers.. Then we looked through daguerrotypes and old cased images we had in the collection, and picked out neat looking frames and parts of the union cases from these. I shot them and took the negs and we made borders for these prints out of the frames from the union cases. We mounted those to one inch black gatorboard and same guy used a sabre saw to cut out them out...we made similar 3D type images out of these as well & they look pretty good.
so, yeah it's a PIA, but it can be done...Putting two pieces together is nothing--you oughta try 30, or cutting mural paper down lengthwise to fit into a 20 inch processor--and then feeding it into the processor without binding it up. That's one of those "look what I HAD to do at work today" story....
I think my advice would be not to approach it as some cherished, master print--but as a display element, or something you can play with and have some fun.