Could the smushy spot on my baby's head cause him to have a learning disability?

No. There is sometimes a squishy area on a baby's scalp following birth which is due to a small blood collection under the covering of the bone (called the periosteum). This will calcify and become part of the skull. It does not lead to learning disabilities.
No. The spot on the top of your baby's head is called the "anterior fontanelle" or the "soft spot". This is a space that allows for the bones of the skull to flex a bit when the baby is passing through the birth canal. It also stays open for a while to allow your baby's brain to grow. So don't worry, it will eventually close over time. If it ever starts to bulge, that could be a sign of illness.
No. I assume you mean the "soft spot, " or anterior fontanelle, and it cannot. It is there to allow his head to squeeze through the birth canal during delivery without causing damage. It is protected and you can touch it. Trauma-- such as shaking or a hard hit-- that produces a soft spot can be extremely dangerous, and these injuries do cause disability and even death in some cases.
No. Babies have a "soft spot" on the top of the head which is an opening in the skull which will eventually close as the bones of the skull grow and fuse together. The brain is protected, however, by a very strong membrane called the dura mater. You cannot cause brain injury by pressure or impact on the soft spot during routine handling.
No. The anterior. fontanelle usually closes between 9-18 mos, the posterior fontanelle between 1-2 mos. Sutures, spaces between bones of an infant's skull, & fontanelles allow skull bones to overlap during delivery without causing pressure on the brain. In infancy & toddlerhood, they allow brain growth & development & protect the brain from damage from minor head injuries. Head growth reflects brain growth.