, welcome to the forum!!!
I'm not sure what to tell you about your tomato problem. It could be disease or pesticide damage. I would probably pull them and pick a healthy seedling up and replant...hoping it's not something in the potting soil or a disease that may have infected the soil. As curled as they are I'd think they're only going to be problems from here out.
When saving tomato seeds you have to treat them with a fermentation process that gets rid of the "pulp" surrounding the seed but that also kills pathogens/disease that may be infecting the seeds. Your friend not knowing what type of tomatoes these are makes me think that he may not have fermented the seeds properly. But, the problem could be something else entirely.
If you're interested in raising tomatoes to eat and want a strong plant with some disease resistance pick up a hybrid. Big Beef, Big Boy, Better Boy, Goliath, Beefmaster, etc., are all common hybrids that taste pretty good and do well. Right now my Big Beefs seem to be outperforming some of the other varieties that I have planted and it has a good old-tomato taste to it.
So, yes, before the season goes much further you may want to pull that one and start over with a possibly a hybrid seedling....home centers, Walmart, etc., usually carry Bonnie Plants which are usually healthy seedlings. Smaller local growers/greenhouses may also have healthy seedlings available. I've never really had an issue with plants from Bonnie, though.
One thing, though. If you replant and have the same problem I would ditch the Miracle Gro potting soil and try a different brand. With the overuse of pesticides (both herbicides and insecticides) these days I believe some of it is beginning to find it's way into processed potting soils and soil amendments. I'm literally afraid to use local cow manure now due to the wholesale use of picloram on pastures and hayfields...the chemical easily ends up in cow manure.
When you replant you might want to mix in a tablespoon of epsom salt in the bottom of the planting hole an inch or two below the rootball. Maybe some finely crushed up eggshells.
Best wishes, be sure to let us know if you decide to replant and how that works out for you!!!