Or maybe they could transport him back his wife ?
I mean this like a weird "solution" , and most likely the least ideal considering the story
The problem was, only Rudy could unlock the way forward.
The teleportation gate has a barrier which only Rudy could unlock (as Elinalise isn't that versed in magic), and they can't reveal the secret of the teleportation gate to anyone else.
Plus to reach the gate it would take over a month of travelling through a monster infested desert, not something you can do if you are not mentally stable. Especially if you have a handicapped person and a few non-combatants along with you as well.
If they tried to avoid those stuff, it would take over a year to reach back home.
Yeah, they could have waited for Rudy to normally recover somewhat, but that would only have bottled-up the issue inside him, which even Slyphe might have failed at solve.
Not to forget, delaying anymore might have plotwise caused Rudy to miss his child's birth.
The main point is that, Rudy had a hard time recovering because he got hit bad on two sides, aka., his father died while protecting him and his mother is practically disabled. So, there was no one close their to support him. And in such case a person, especially men feel far more alone than what others might think.
If Zenith had been ok, then Rudy wouldn't have suffered so bad.
On another note, if you consider wars in the olden days, it was common for soldiers (even married), to turn to prostitute (or even outright rape) to get over or divert attention from their trauma aka., PTSD, they got because of killing people. If I say, this might even apply in current era as well.