I think there is a bigger issue for him, muslims are actually not allowed to attend the actual funeral of non-muslims ( it is a Islamic directive), they are supposed to stand up and show respect during the funeral procession for Christian/Jews. So it would be a bit awkward for him to attend to stand by as the coffin is taken for burial but not go to the actual Church ceremony etc.
However from Mo's tweet I think he is taking this very very hard and the fact that he mentioned being fearful of returning knowing that Jota will not be there kind of explains the depth of feeling he is experiencing.
Oh the funeral was at a church - makes sense. Mo probably would have got stupid hatred, like he does on Christmas every year, had he gone ... he kept that shit away from the day ...