Angenas knows he's a failson, which is exactly why they support him. If they can put Viesel in charge of Lombardi he's easy to manipulate and destroy Lombardi's position. Then Angenas can take over Lombardi's resources and businesses. He's a useful idiot.
Where I agree with you is asking why the rest of Lombardi hasn't stripped him of his titles or even jailed him for associating with Angenas. It should be clear that he's more loyal to an outsider family, thinks only of his own prestige, and is an incompetent manager. Under no circumstances should Viesel be allowed near their businesses. By now they could have easily proven him to be a traitor and eliminated him.
Definitely@Angenas. If it wasn't for that conversation with the patriarch of Angenas, I might've considered that they also grew tired of his shit and threw him out.
But, nah...using him is more the Angenas way.
Rulac still thinks of this twit as his son, so that's currently his only saving grace. The idea of keeping your friends close, but your enemies closer, also comes to mind. I just hope they act appropriately, but it could be that Viesel was placed in this position on purpose so he could be closely monitored, despite not being severely punished.
Taking a step back, this isn't much different from typical family politics, just on a grander scale because it involves people of high society. I doubt he'll be able to do anything too effective against Tia besides making himself a nuisance. We all know that "child" is a lot smarter than him, very well connected, and very influential despite her age. And Shannet probably knows that, or has a very strong inkling and a great deal of respect for the abilities of her niece. Knowing the character of Uncle Viesel, he'll probably embarass himself in a spectacular fashion again. Probably try to gain some accomplishment to put his pride on display which publicly proclaims that he is the indisputable leading candidate who should be head of the family. Only he'll focus solely on his pride as usual, and do many stupid things, allowing for many holes to easily be poked into his plot, and then get shredded.
Maybe this time, involving a legally heinous crime for which he can be charged then prosecuted. At the very least, lose his standing completely, be tossed out, and be forced to live in utter humiliation as what he despises the most...a commoner.