I don’t know an expression exactly corresponding to "to hell and back", but you could keep reference to hell with the following sentences.

If the terrible situation improved in the meantime (wife is better):

J’ai vécu l’enfer lorsque ma femme est tombée malade (mais la situation s’arrange)

If the terrible situation is still ongoing (wife is still ill)

Je vis un enfer depuis que ma femme est tombée malade

If you don’t necessarily want to keep hell reference, there are a lot of other possibilities. A few:

La situation est vraiment compliquée depuis que ma femme..

C’est pas la joie depuis que ma femme…

Je traverse de durs moments depuis que ma femme…

The idiomatic phrase “rescapé de l’enfer” answers fairly well the need to render “to hell and back” in French. From the definition of “to hell and back” which is “to have gone through a difficult situation” and which implies clearly that this situation was overcome and is no longer extant, or in other words that the persons involved were so to speak saved from it, we can see that “rescapé” corresponds well. Let’s note that “rescapé de l’enfer” is used in this particular figurative sense but more often with a qualifying term for “enfer”; this can be verified from a check of the books collected through this ngram. Here is one instance.

• J’ai ressenti presque de l’admiration de leur part d’être un rescapé de l’enfer nazi. Je recevais des chocolats, des gâteaux…, c’était la première fois de mon existence que je mangeais tant de friandises que j’avalais sans retenue et en quantité

Here is another.

• Cher DSK, Vous voilà rescapé de l’enfer, couvert de brûlures, de crachats et de plaies, sous les cris de haine, de mépris, ou le silence assourdissant de ceux qui n’en pensent pas moins – ou que tant de remue-ménage arrange bien.

In the particular sentence examined in the question there is a problem. It is unfortunate that to grasp it a long digresssion must be made into the notions of telic verbal forms. The tense is correct as far as go the possible tenses used with “since”, but “since” doesn’t correspond to the verb phrase “to be to hell and back”, as this is a so called telic verbal form.

In linguistics, telicity (from the Greek τέλος, meaning “end” or “goal”) is the property of a verb or verb phrase that presents an action or event as being complete in some sense. A verb or verb phrase with this property is said to be telic, while a verb or verb phrase that presents an action or event as being incomplete is said to be atelic.

Looking up the definition of “since” as it is used in the sentence of the question, we get this (OALD).

• (used with the present perfect, past perfect or simple present tense in the main clause) from an event in the past until a later past event, or until now

(I assume that the sense of “since” here is not the other possible one for this conjonction, that is “because”, “as”.)
From this definition you understand that the action of the verb (rightly in the present perfect) must last to the time of the present, and this time is the time when the locutor is uttering this sentence, or, in other words, “the locutor’s present”.

As is reminded us in this article, the usage describes since when something has been going on and “since” is normally used, and, as well, the present perfect continuous is also often used [that is the present perfect and the present perfect continuous are nearly equivalent in this context].
We see this near equivalence in sentences such as the following.

• We have lived in Sapporo since the year of my graduation. (atelic)
• We have been living in Sapporo since the year of my graduation.

Here are examples where the telic aspect of the verb stands out and makes it clear that such verbs are not compatible with the construction “present perfect – since”.

You can’t say that.

• “I have had a haircut since the month began. (telic, you must be out of the barber’s chair before the action is done.)

You can’t say that either; this is more obviously impossible.

• I have been having a haircut since the month began.

However, you can say this.

• I have had haircuts since the month began. (atelic because “to have haircuts” is not an action that has to get to a given stage before we can say it is extant: at each given haircut or at any time between haircuts and during haircuts, those times being just stages in the action of having haircuts, the action is effected; this is as for “to live” (atelic)).

• I haven’t had [[a/one/one single] haircut/haircuts] since the month started.

Why is there a notion of atelic action here and what is atelic? The atelic notion is in the phrase “to have haircuts”, which is the affirmative form corresponding to “not to have [[a/one/one single] haircut/haircuts]”. The denial of an action that is not specified as to when it happens in a given period is an atelic “action”. Here is an instance in French.

• J’ai vu ce film depuis que le président a été élu. (telic, an impossible construction, unless you mean some sort of repeated occurrences of seeing the film and then it must be made precise or the sentence sounds ambiguous (plusieurs fois, souvent, quelques fois, une fois, etc.))
• Je n’ai pas vu ce film depuis que le président a été élu. (atelic, the negation (lack of action) makes this “absent action” immaterial over time, therefore extends it to all the time considered)

Notice that you can say “I have had a haircut (and bought a shirt) since the month began (but I made no other buys).”. The action is atelic because the haircut is considered from the point of view of being a buy.

You can say that.

• I have had problems with this engine since the month began.

You can also say this.

• I have been having problems with this engine since the month began. (telic)

Another example

• I have eaten only stale bread since the month began. (telic)
• I have been eating only stale bread since the month began.

In consequence of this syntactic point of view the sentence could be as shown below.

• I have been to hell and back right after my wife became ill.

There is still no limit on the time during which the person is “going through hell” and the action can stop any time before his wife gets well, or, just as likely an eventuality, it can go on. Such a sentence I’d translate as follows.

• [Je suis devenu/J’ai été] un rescapé de l’enfer après que ma femme est tombée malade.