My hypothesis is that he's related to Tybalt, by which I mean Jade was married to someone before Burke and that person is Tybalt's birth father and Lynette's brother or father.
But that would still make Jade his Aunt and even non-blood relatives are considered incest under Patreon's TOS and under the law in the U.S., so this is probably not what it will be.
people keep saying that MC could be related to a B or R but that's lazy writing. MC mother is not related to B&R. you could be rich without being related to a B&R. So why everybody thinking about that?
It's not lazy writing, I don't see why people think it is. It actually has the potential for being a greater impact on the MC and the dynamic of their life than if they were related to some random rich family that we've not heard of. It would be especially impactful if he becomes the "prodigal son" type character where his Mom was the first-born child and thus the one who would have inherited most of the family wealth, legacy, power, etc, because it puts him in a technically higher position than Rusty if his Dad were the 2nd or even 3rd born.
Of course, the MC doesn't have to accept it and can try to live a normal life, but people could perceive him differently and it could affect his life whether he wants it to or not. It has the potential to be a huge, game-changing moment for the MC if he were to become a Burg, especially if he were to be the heir-apparent of the Burg family.
Lynette father owns a construction company. So, why people think MC is related to a B&R?
It's not stated that her Dad owned a construction company, only that Neil worked in construction and was hired to build a hotel for this "flithy rich" guy.
Even if her Dad did own a construction company, most of the big ones are owned by millionaires, or they're owned by capital or investment firms that are owned by billionaires. Most millionaires and billionaires have their fingers in many different pies and own companies/run businesses in different sectors, or at least have investments and stock tied up in different areas.
So it's not impossible to believe that 2 rich men founded a college and that their families have gone on to become incredibly wealthy and have business interests in a few different areas, including owning and operating hotels. It would be like if the great-grandfathers of the Walton and Pritzker families had founded a college together.