My DH is strongly against giving a sperm sample (he has other children but doesn't want to do his thing in a doctor's office--it weirds him out) but is 100% okay with using DE.
My question is, can unfertilized DE's be placed into a woman's tube(s) and allow natural fertilization to take place?
To do DE IVF your husband is going to have to provide a semen sample. Probably once as part of screening for routine semen analysis, then one for fertilizing eggs at retrieval. They like to have a frozen one as backup as well.
He doesn't have to produce the sample at the clinic, he can produce it at home and bring it to the clinic, or if you live far he can produce it at a hotel near the clinic and bring it in. If he can't produce or has some kind of phobia about The Cup, he can arrange in advance for a urologist to aspirate sperm directly from the testicles.
The process where they put unfertilized eggs and sperm directly in the Fallopian tube surgically (GIFT) still requires a semen sample in advance. They mix the eggs and sperm together in the lab but put the mixture in the recipient before fertilization takes place (for religious reasons some people can't have fertilization take place outside the body, and GIFT is a way around it).