Anything in the way of practical support is really what is needed. For example - washing, ironing, cooking and baking would probably be welcome. What about offering to do a shop? Perhaps you could offer to co-ordinate a telephone update service for friends? It is exhausting to be constantly answering the telephone whenever you have spent all day at the hospital and just want to sleep. How about offering lifts to and from the hospital? the cost of parking at hospital is crippling. Also - if the child is in hospital, CDs are nice to listen to - holding a book can be a pain if you have got an IV stuck in your arm.
Hope all goes well - the prognosis for hodgekins is usually quite good.