Hi and welcome to YT. Your little one sounds precious. In time with a good diet, his hair will come in. Hot Rod hair was/is very straight and smooth. It does seem to get slick much quicker than Maggie Mays. I have decided to keep him short because when it does grow any length, it tends to look scraggly.
But with it cut short, his hair is soooo shiney and and clean looking.
I would definitely look in the health and diet section for information on good foods for your little one. Hot Rod was 1.57 lbs when we got him at 15/16 weeks. I was afraid that I was going to break him. It took every bit of 5 months to break 2 lbs! He's now very robust at 4 1/2 - 5 lbs.
Good luck with your little one!