I think he will not find a visa problems i think he should go to the UK consulate in Morocco they will give him all information, instruction to follow and forms that you will need maybe you can see that in their website you google UK consulate in morocco and you might find the website and for the marriage is going to be a Moroccan one i mean with the government of morocco and this marriage certificate and forms that he is going to get from the consulates and he will collect all documents that he needs in they instruction what is going to qualify you fiance to get his visa .
NB: you will also have document to send it to your state too .
Have a good day
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