The question you propose is probably not a good fit for MSE. Questions on MSE should be narrowly focused and of broad interest to the community of mathematics students and mathematicians who comprise the user base of MSE. You are essentially asking someone to proofread your thesis (or, at least, the mathematically intensive portions of that thesis), which is neither narrowly focused nor of general interest.
What follows is off-topic for this website (though your question might be on-topic at Academia SE), but I'll offer my opinion:
It is unfortunate that you are no longer working with your advisor, as the kind of proofreading you are requesting really is part of the work of an advisor. Your first step should probably be to reach out to your advisor and ask for help or, barring that, find someone else in your department who is willing to advise you long enough to finish your degree. Indeed, you are probably going to have to get someone to agree to sign your completion paperwork in the place of you advisor; in an ideal world, that person ought to be helping you with your work.
Alternatively, if you need someone to check your math, I would recommend having a chat with someone in the mathematics department of your institution. You ought to be able to hire someone to help you out (and you should be paying for their services—what you are requesting is a pretty big ask).