As salamu alaykum dear sister,
Children are often naturally shy at this age and sometimes afraid of people they don’t know. It is a normal developmental stage which insha’Allah he will out grow. However, his dad hitting him and yelling is not appropriate parenting. If it continues, yes, your son could develop a complex in addition to feeling insecure and having low self esteem when he gets a little older. There are may ways to deal with a young child’s behavior other than hitting and yelling. I highly suggest sister, that you and your husband take some classes in parenting skills. Many community centers offer them and they provide positive ways to deal with mis-behaving children that encourages healthy growth & development insha’Allah. It appears that your husband takes his anger out on your baby, which is not right. It must be addressed. I would further suggest you encourage him to seek counseling or speak with your imam about the situation. Perhaps there are some Father Groups at your Masjid or within your local Islamic community. If he is a new dad, this could be most beneficial. We wish you the best, you are In our prayers.