Being approved for Social Security Income?

My husband is in his late 20's. Suffers from Kyphosis disease which restricts him to standing for long periods and lifting object 50lbs+. He also suffers from Congenital Heart defects and it makes him p out if he is too stressed out. He may also have Arthritis in his right hand. He has an excellent work history but had to be excused from his first job after ping out. Every job that he desires to work for; he fears of either his back going out on him or ping out again. I suggested he file for SSI because I'm very fearful of him injuring himself or the unthinkable. I love my husband dearly and I was wondering if he has a chance? He is afraid of filling out the paper work for it because of denial. He figures he is too young and hasn't worked long enough. He has 8 yrs. work under his belt and is in his late 20's (as stated before). Thank You everyone for reading.