Can an Jewish, intermarried, non-Shabbos observant father of the kallah (or chosson) recite a bracha of the Sheva Brachot under the chuppah? What are the halachic sources for who may say these brachot?
He should not recite any of the brachos under the chuppah. It should not be insulting at all, because at most weddings, the father of the chosson and kallah don’t say any of the brachos etc. under the chuppah. It would be advisable to speak with the Rov who will be the mesader kiddushin, exactly how to work this out. See sources
Igros Moshe Y:D, 3 106 (2), O:CH 2 50-51, 3-12,21,22, 5-13(6). Binah V’daas 23-13.