He can request any amount he wants but unless he can make the business case to potential sponsors, he isn't going to get it. If he doesn't get it it is because he is:

1) Simply not worth it or;
2) Is worth it but was not able to show potential sponsors why that is the case.

My guess is 1 would be the reason and there is no compelling case he is worth 100k to sponsor.

But aside from that, from all the personal issues that make him unfriendly to a sponsor (contrary to popular belief - not all publicity is good when it comes to brands), what effort has he given to show the sponsors they will get more than the 100k back?

If I were in his shoes, I'd have a package generated that I could send to all potential sponsors. It would include what I will do for them in terms of promotion, the social media reach numbers, any past deals with conversion rates, etc... Anything that can show the potential sponsors how they will recoup their investment.

Though, I think a lot of people in the BJJ space also believe sponsorships are more charitable than a business transaction and for a lot of businesses that sponsor athletes - it is more charitable/out of passion.