I started my first job after university last September in an industrial company. I work as a programmer in a team of three people (only development). In October, a colleague of mine -- let's call him "Bob" -- presented a project he has worked on for about 1.5 years. It was supposed to be complete, but wasn't even close. After the presentation he got a new deadline, which just passed last week -- everyone in this meeting was pretty mad at him.
One of my (many) tasks assigned by our department leader was to help Bob finish his project -- no pressure, just along the other things. Bob was told that I "should work for him full time," which I did for about two weeks before I got other things to do. Around Christmas I got my own project and asked my supervisor how I should prioritize my work, especially the work for Bob. He told me I could drop it if I had other things to do. I wanted to talk about it with Bob but our supervisor told me not to talk about my project with Bob at all. He said he would talk with Bob but he didn't (I guess).
Bob chose a technology for his project that I have hardly any knowledge of, and I had a lot of difficulty working in the project's development environment. I had a lot of issues with the firewall, which Bob does not have because he works remotely. Bob tried to help me with the new technology and my problems and our development environment, but sometimes even he couldn't figure out if the problem was me or caused by the firewall, so that made clear that I wasn't able to support him directly but I tried to help him with other things, such as organizing meetings with future users. I sent him everything I gathered about the requirements, made some diagrams, wrote them down - just like his secretary. He said thanks, but didn't give me any new tasks after February.
Another presentation was held after Bob's second deadline, and it was disastrous. There wasn't any new functionality for the users. Not one of the requirements was fulfilled. Bob told them he worked a lot on background functions. He blamed them for setting the meeting a week earlier than he hoped for, and even blamed me for not helping him (but my supervisor defended me). Bob got a six-week extension of his deadline.
Afterwards he even complained to my hiring manager -- "Alice" -- for not using his chosen technology (which he thinks should be used everywhere) in my project, even though that was not a requirement. Alice did not attend Bob's presentation.
Bob asked our supervisor to assign me full time again to help him, but our supervisor left it up to me how much effort/time I want to spend for Bob. He recommended me not to get involved.
How should I professionally interact with Bob ever again? My goal is to keep my job and my sanity.
Update: I wrote Bob an email to offer him help with anything else than programming, he said thanks but never contacted me again. About two months were gone now and the last deadline for Bob passed away. He could not show anything new, so the company decided to cut off the whole project as well as Bob.