On reddit the developer has stated multiple times that this is a search partnership and not a buyout. The blog indicates that it is a buyout and so does the change in company director. That makes me confused as to what is happening here.
Also, Alex appears to have stepped down as director of Waterfox and a co-founder of System1 became director: https://beta.companieshouse.gov.uk/company/08071145/filing-h...
Sad news indeeed; I loved Waterfox:(
Also, If he would have asked for help, I'd have happily donated some quid.