Yes, it should've been removed well before the decay started; this was an inevitable result. It will be a surgical extraction requiring lifting up of the gum, then severing the tooth in 2 planes - first light green to remove the crown part, and then possibly dark green to divide the roots. For a competent general dentist, that is quite achievable; for an oral surgeon it'll be easy.
There are a few risks, as with any procedure:
- the filling in the 2nd molar may be damaged and need repair at another appointment. My first step before raising the gum would be to slice off the back edge of that lumpy amalgam (yellow line) to minimise this issue, and make the extraction easier.
- The red lines show a major nerve bundle (the IAN) under the root tips. There's always a risk of damaging it, particularly if there has to be any digging around deep in the socket to chase broken roots. I see it as really unlikely.
- If a root tip DID break during the extraction, it is reasonable to sometimes leave it in place and let the bone heal over.
- There is another nerve just on the inner side of the wisdom tooth - the lingual nerve. Again, very small risk of damage in your case in hands of competent dentist.
- Then there's the usual issues - pain, bleeding, bruising, possible "dry socket".
I'm guessing you're in early 30s? The bone where the wisdom tooth comes up will fill in with new bone over several months. Because this extraction has been delayed, the bone at the back of the filled tooth (blue arrows) will NOT fill up. You will have to work extra hard to keep the back surface of that clean for the rest of your life.