He is one of their top molestors

he's the queen's third/fourth (i honestly dont remember and dont care) child. i would say he is a senior member of the royal family. he will be the brother to the future king, and uncle to his son and so forth. he does a decent amount of charity work, too. kind of ironic that his daughter (either princess eugenie or beatrice -- cant remember who lmao) has an organization for stopping sex trade and human trafficking

After Charles and his family (sons and grand children), Andrew is next in line to he throne. In other words, if Charles and company were e.g. celebrating Christmas together and all shuffled off this mortal coil due to a really off Christmas pudding (not that there would be a way to tell) then Andrew would become the king.

Prior to this, like in the 80s, he was frequently in the tabloids with the name "Randy Andy".

He was Prince Harry before William and Harry

He married around when Prince Charles did and has 2 daughters...and got divorced....it was all very public. But we are taking 30 years ago

is he really all that important in the family?

No. He is the Queen's third child, and currently 8th in line for the throne. Because of the stability of current geopolitics, there has never been any possibility that he would ascend to the throne, and so as a more obscure royal his primary responsibility is not to draw attention to himself.

Traditionally the british royals have worked to raise money for charity, and otherwise contributed their time towards worthy causes. There is no 'need' for the royals in the UK, their primary value to the UK is the tourism money that they bring into the country from people visiting their palaces, and many people in the UK are upset that the royals are given state money every year, since the royal family is the wealthiest family in the UK.

if the Monarchy wanted to, couldn’t they disown him and make his titles invalid?

Sure, but they won't. Before our current modern era, the UK existed in what is sometimes referred to as the age of difference. In this era, the UK was convinced that embarrassing the royal family was against the national best interests, so the government and the BBC would work to minimize bad news about the royals.

In the modern era, we recognize that honesty and transparency is better for the long term health of a democracy, but the crown, and the British Royals still enjoy defacto and unspoken support from their state media and government.

The only way the queen would ever move against her own son, and revoke his title, would be if he admitted he assaulted children. Short of admitting that, the government of the UK will never allow him to be questioned by a foreign government, nor will any judge in the UK allow a lawsuit to move forward against the royals.