Not all four-year-olds can read, and it might be even less likely in one who has been neglected.
But if you want to give him something he has the best chance of being able to read, try:
The Bob Books, published by Scholastic. These come in a little cardboard box, about 10 paperbacks each about 10 pages long, with line drawings. They are the easiest books to read ever, with nothing but three letter words, for example: ``A big cat at the zoo had a bad leg. The vet had to fix the cat.’’ These give the new reader confidence, because he is able to read the entire story, usually, himself.
Harper McMillan publishes a number of small paperbacks with collor illustrations called ``An I Can Read Book.’’ There are funny and charming stories, and restrict themselves mostly to short sentences and words. More advanced than the Bob Books, uses the silent e, for exmaple.
Another excellent set on this level are the ``Henry and Mudge’’ books by Cynthia Rylant and Sucie Stevenson. Adventures of a rather independent boy and his big drooling dog, easy to read, very charming. These were the number one favorite of my boy when he was four.
Additionally, I would be cautious about LEGOs. Modern LEGOs have many very small parts, which can be hard to assemble and disassemble with small uncoordinated hands. Following the assembly instructions can also be challenging. They do have large-scale LEGOs (Duplo) which are designed for younger children.
If he has been bounced around a lot, he may well have a strong need for what are called ``transitional objects.’’ You might be able to find a stuffed animal which has a small zippered pocket in it to store things. This might be a good present, as it gives him a little tiny corner of his own space. Someone who has bounced around a lot is lacking in continuity, and being able to identify a small space that goes with him everywhere might be nice.
I’d be surprised if he really liked a toy gun. That’s something little boys get into during school age.