My best friend and I have been visiting her 85 year old Grandfather in the hospital every week, sometimes 3 or 4 times a week for the past 2 months. I have a weak immune system, and although I know better than to spend much time in a hospital, her Grandfather has the MRSA staph infection, and pneumonia, so I am really not sure how much time he has left.

I read online last night that MRSA staph infection is highly contagious, and presents itself as a blister or a sore, and in severe cases a rare pneumonia can develop. My question is whether anyone knows the possibility of contracting the staph infection in a different form, one that presents itself as illness without sores? I didn't see much info about that on the internet.

Any info on MRSA infection would be greatly appreciated!

Yes, it can present itself as illness without sores and you are very correct in being cautious about this auto immune disease explained on wikapedia. I may be repeating what you have read already but no harm in viewing it again:

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium responsible for difficult-to-treat infections in humans. It may also be referred to as multiple-resistant Staphylococcus aureus or oxacillin-resistant Staphylococcus aureus (ORSA). The organism is often sub-categorized as Community-Associated MRSA (CA-MRSA) or Hospital-Associated MRSA (HA-MRSA) depending upon the circumstances of acquiring disease, based on current data that these are distinct strains of the bacterial species.[1]

MRSA is a resistant variation of the common bacterium Staphylococcus aureus. It has evolved an ability to survive treatment with beta-lactam antibiotics, including penicillin, methicillin, and cephalosporins.[2] MRSA is especially troublesome in hospital-associated (nosocomial) infections. In hospitals, patients with open wounds, invasive devices, and weakened immune systems are at greater risk for infection than the general public. Hospital staff who do not follow proper sanitary procedures may transfer bacteria from patient to patient.

Since you have a weak immune system, I would strongly suggest you stay out of a hospital setting.