Maintenance Pending suit

Hi, I am hoping you help. So my partner (male) earns more than his separated (5 years) wife. He has gotten into considerable debt trying to keep things going during and after the separation and now in the past few months just pays whatever he has left which is not enough to cover her bills. She refuses to go to work and uses her sons (16) made-up illness (no evidence will or needs to be provided to the court apparently) as an excuse. I am looking to understand if he can be forced to pay the Maintenace Pending Suit even though after his basic bills are paid with some money put aside to spend with the kids and a £1700 contribution to his wifes bills (about half), can he be forced to pay a Maintenance pending suite? So far, the courts appear to have not seen through her manipulation and to me, as a woman, its seriously concerning on so many levels.

How much does he earn?
How much has he been paying?
Why and for how long?
If 16 year old son has an illness that prevents her from working then there must be a diagnosis in place and they must be eligible for benefits. For her not to be able to work his needs must be quite complex.
Potential issue from your post it looks as if he may have been paying a considerable amount for some time. If so then he has acknowledged that she has a need and demonstrated that he has the ability to pay.

He takes home 5k and he has been paying nearly 13k each month to keep the bills paid, he cashed in everything he had, however, there was no other way to pay everything and she would not reduce any of her outgoings that were not essential. So after he has paid his basic bills/needs he gives her everything that is left. Although it's not enough. They want £3k but he doesn't have it. However, I am more and more concerned the law does not seem to care! With regards to the son, he has nothing wrong when he is with his dad, he is with mates most of them time and goes to the gym, is about to get a job. The court needed no evidence of his suppose illness, its all very one sided.

Just to clarify he has been paying his ex £13,000 per month for bills?
what bills come to that much every month?
If the son is disabled to the degree it prevents his carer from working the court will need to know the details.They don’t just accept someone saying they cannot work as they look after a 16 year old.
your partner needs to get his act together. What he is doing isn’t sustainable.