If you're buying only $2 worth of bitcoin per week, realistically, it only means that you're going to accumulate less than $400 worth of bitcoin per year and even in five years time, the amount of bitcoin you would have accumulated would be too little to place you at a good profit as bitcoin price grows.
While that's some truth there but this is still better than the majority of those people that only watches the price of Bitcoin and are all just in their mouths talking about they should buy soon.
Consistency is the key into profiting and if someone who's able to invest $2 only per week. It's better to keep that and do a lumpsum maybe every 2 months because if it's done per week, the fees might flatten and lessen the value of that amount.
Bitcoin generally favours those that have more capital so in addition to having a right investment plan, it's also necessary to work on having a good amount you're hoping to use in your investment.
Like increasing a dollar or two if it's possible. But as long as he's consistent doing it, he's still better than the rest that don't take action.