Are you sure it is the same buck? Both deer appear to be young bucks (~1.5 years old).
Typically, deer that are susceptible to the virus and display cutaneous fibromas one year are immune to reinfection thereafter. That is why you usually only see them on younger animals.
The fibromas or deer warts usually regress during the fall and winter. Some deer are completely immune from the start while others have varying levels of resistance initially.
Also don't sell deer/wildlife short, it isn't feeling sorry for itself and it is really amazing what they can sometimes overcome and go on to lead a healthy life. Although, as everyone has noted, this buck is in poor shape - there may also be something in addition to the fibromas that is contributing to its condition.
Take Care,
Tom