That he isn't walking yet is absolutely okay.They need to be cruising by 15 months, and walking by 18 months before it is a concern. The average time to start walking is 13-15 months. You have time.
The cruising with one foot tip-toe is a bit worrisome, unless he only does that occasionally.
That could be a sign that one foot won't distend properly, or even a sign of autism (they tend to be full time or nearly full time toe walkers).