This all sounds very, very dodgy. Starting with wondering what kind of mess the friend has gotten himself into where he has to pay all of this money back at once. I've never heard of a business that wouldn't accept payments when trying to recoup money owed to them. That makes it sound like something illegal, first of all.
Second, when this guy is insisting on lying to both spouses, you and his wife, both of their supposedly nearest and dearest people, well, that makes him a serious liar, doesn't it? He's also making both of you complicit in his lies. Your husband isn't supposed to tell you and now you're keeping critical information from his wife, who is your friend. Very shabby treatment by someone who's going around begging. Also then, why should anyone believe the rest of his story?
Third, his lies prevent a fair and reasonable solution, like maybe his wife go to work and help out her own family, rather than continuing to enjoy a life of leisure and vacations, unaware, while you and your husband pick up the slack and cause damage in your relationship? His wife has a right to know what's going on with her own marital finances.
Fourth, combined with the sketchy dubiousness of this whole deal and having no problem lying and asking your husband to lie (which also smacks of misogyny, by the way), the suicide threat is extremely manipulative. Maybe your husband should call for a mental health check on him instead, if he's so suicidal.
None of the above describes someone who is taking any responsibility for his mistakes. Instead, he lies and uses emotional blackmail to try to get your husband to stupidly put himself at risk instead and cause problems in your marriage, while his remains blissful, due to his lying.
However, those are all HIS problems. YOU have a "husband problem." He is not looking out for you or putting you first as he should. Instead, he rolls over like a sap, preferring to play the hero to his stupid friend, based on a sob story. All to the detriment of his own family, in more than one way.
Since he rolls over so easily, I would put your foot down. After all, YOU have the right to, unlike his irresponsible friend. I'd tell him in no uncertain terms that since you are a marital unit, business or not, it's NOT his right to do this without your consent, which you have not given.
Insist on marriage counseling before you'll even consider allowing him to drag your family into his sneaky, stupid friend's mess. He needs a strong reminder of his priorities and duties here, and "people pleasing" is not on the list.