The religious cleric can be the agent of the husband or the agent of the wife if one of them is not present at the place of the contract.
Islam is a divine religion that Almighty Allah revealed to guard the welfare of people. Almighty Allah knows the reality of things and what benefits His slaves, so He set laws accordingly for them to observe. Since Islam is the seal of religions, these laws are for until the end of this world. Because of corruption, badness and evilness in certain things or acts, He commanded us to refrain from them and made them prohibited. Similarly, because of benefits and goodness in certain other things, He ordered us to perform them and made them obligatory on us. Some of these laws are general and apply to all people, all the time, and anywhere.The ability of the human being is limited, so is unable to find out and understand the reasons behind the Sharia of Almighty Allah. Sometimes Allah Almighty has taught us through the Holy Prophet and the Imams (peace be upon them), the wisdom behind certain few rulings. We must obey His laws by refraining from the prohibited acts and undertaking the obligatory acts, even if we do not know the reason behind each and every one of them.The najasah of the dog is one of the rulings about which we do not know the wisdom behind.
The best way to avoid doubts is to ignore them. It has been narrated that a person will not be held accountable because of excessive doubts. A believer should not pay attention to doubts as doing so is considered as a decrease in one's faith.
If his body is bent like that permanently in such a way that it cannot be placed straight, then it is not obligatory to straighten the body.