That can be done, yes. It is a fairly common use of WordPress. I’ve seen many plugins that help you do just that. As plugin recommendations are off-topic, I’ll leave choosing to you.
What I will do is outline a good approach to working on such a project.
Step one – know exactly what you need
Before you start installing stuff, make a detailed list of the features you want now and may want further down the line. Talk to your brother about this because changing plugin later will be a massive hassle.
Devide the list into must have, would be good to have, and nice but can live without.
Talk about budget with him. Many plugins have paid version with more features. This may or may not be right for your project.
Step two – figure out what is available.
The fewer plugins you need to do this the better time you are likely to have getting them all to work together. Good custom theme work can cover a lot of cracks here.
Identify you options and grade them on how well they meet the needs you listed. Reject anything that does not cover the must haves (that another plugin cannot fill in for).
I’d combine googleing for lists of “best X for Y” type posts with searching the WordPress repository.
You should now have a short list of the things that best meet your needs. If not, you may need to hire someone to write something for you. Comisioning something custom is going to hurt your budget so be aware of that going in.
Step three – try some stuff out
In whatever way you can, spin up a dev, local, test, whatever copy of WordPress and try out some of your best ranked options. This will show you any gotchas, headaches, or poorly working plugins.
Illiminate any options that are too much fuss, don’t work, and/or have poor support. You are looking for a set up that is within budget, is workable at your skill level, and has good support when things go wrong (and they will).
Step four – customise as needed
Now you have a favourite (hopefully) it is time to pair that with a good theme (repeated the first three steps for the theme too – you want something that will work well with your plugins and that looks the part).
Step five – roll it out
Now you are ready to hit the go button.
If what you have is not working, reload early. Its much less painful to reboot with new choices when you only have a small user base.
The best teacher is just giving it a go. In the worse case, you will have leaned something for next time.