Marrying a non EU citizen

Hello, I am new to the forum and am hoping that someone can point me in the right direction.
I am an Irish citizen living in the U.K. for over 33 years and wish to marry my Brazilian fiancé.
He is currently here on a visitors visa which he got at point of entry. Due to ill health, I am on PIP and ESA and really need him here to help me as my carer.
What is the best route for us to go down ie exercising my rights under EU law or applying for a visa to marry under U.K. law. I am unable to travel to Brazil to get married due to my ill health and my fear of flying. So we are left with a dilemma, do we do a proxy marriage in Brazil, try and get married in Europe (but not sure if my partner would be refused entry back into the U.K. even with a marriage certificate) or go through the lengthy process and the cost of applying for a fiancé visa and then a spouse visa in order for him to live with me in the U.K.?
Thank you in advance for any advice.